Products from the decomposition of plastic waste

ABSTRACT

This invention relates to the field of plastic waste decomposition. More specifically, the invention comprises products obtained from the decomposition of plastic waste.

FIELD OF THE INVENTION

This invention relates to the field of contaminated plastic wastedecomposition. More specifically, the invention comprises productsobtained by decomposition of plastic waste.

BACKGROUND

All publications herein are incorporated by reference to the same extentas if each individual publication or patent application was specificallyand individually indicated to be incorporated by reference. Thefollowing description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

Plastic pollution is a global environmental crisis for many reasons.Plastics are made to be durable rather than degradable. The ones thatare biodegradable demonstrate shortcomings such as high production costsand functionality problems, which result in their challenges to beproduced or used on a large scale. Furthermore, the existence of a largevariety of plastic polymer types has led to an increase in publicconfusion on the subject of what is recyclable. Plastic consumerism isinevitable and continues to grow. Not only is existing plastic pollutionprevalent and ubiquitous, but new plastic waste is generated at analarming rate. This global excess of plastic waste harms the environmentand pollutes the food chain.

A common component of the municipal waste stream and marine debris iscontaminated plastics or contaminated plastic waste. Current methodsthat exist for the treatment of contaminated plastics or contaminatedplastic waste include pyrolysis, incineration, landfill disposal, andmechanical recycling after thorough cleaning. Plastic pyrolysis isenergy intensive and produces low-grade fuels that require expensiverefinery steps to be useful chemicals. This cannot be economicallyaccomplished. Plastic incineration requires massive amounts of upfrontcapital to establish, needs substantial power and maintenance, and alsoresults in adverse environmental consequences, as does the disposal ofplastics in landfills. These expensive methods pollute the environmentand do not utilize the contaminated plastic waste materials that couldbe used as a raw feedstock for new products. Almost all post-consumerand post-industrial contaminated plastic waste are centralized tomaterial recovery facilities, where they can become furthercontaminated. Mechanical recycling is not economically viable becausecleaning contaminated plastics or contaminated plastic waste requiresintensive resources and labor.

Less than 15% of global plastics produced is recycled because theprocess is not economical. As much as 50% of recycling bin content inthe United States is considered contamination and is normally discardedby the traditional recycling process. Even though plastics are the mostabundant materials in the waste recovery stream, they are the leastpreferred material for recycling because most plastic, with theexception of water bottles and milk jugs, have few or no viabledownstream markets. In 2014, the EPA has calculated the amount ofplastic films not recycled was 3.6 million tons. Since then, packagingplastics have increased in volume at waste plants due to the wideadoption of food delivery and online shopping.

Although much research has been done on the bioremediation of plasticpollution, biological methods alone are expensive, inefficient, anddifficult to scale. Such techniques, including those involving ex vivocellular degradation or insect larval digestion, also have not coupledplastic waste treatment with the production of value-added economicalproducts.

Thus, there is a need in the art for methods and systems that providefor the decomposition of contaminated plastic waste that overcome thelimitations of known methods.

SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, compositions, methods, andarticles of manufacture which are meant to be exemplary andillustrative, not limiting in scope.

In various embodiments, the present invention provides a method fordecomposing contaminated plastic waste, comprising: adding contaminatedplastic waste to a reaction vessel; adding at least one oxidizing agentto the reaction vessel; and subjecting the contaminated plastic waste toconditions effective to decompose the contaminated plastic waste toproduce a decomposition mixture.

In some embodiments, the method further comprises adding at least onesolid state catalyst to the reaction vessel.

In some embodiments, the conditions comprise a temperature range; aninitial pressure range of a gas; and a residence time in the reactionvessel.

In some embodiments, the contaminated plastic waste comprises at leastone plastic material; and at least one non-plastic material.

In some embodiments, the plastic material comprises at least oneselected from the group consisting of plastic film, plastic foam,plastic packaging, plastic bags, plastic wrap, and combinations thereof.

In some embodiments, the plastic material comprises polyethylene.

In some embodiments, the plastic material comprises at least oneselected from the group consisting of very low density polyethylene, lowdensity polyethylene, linear low density polyethylene, medium densitypolyethylene, cross-linked polyethylene, high density polyethylene, highdensity cross-linked polyethylene, high molecular weight polyethylene,ultra-low molecular weight polyethylene, ultra-high molecular weightpolyethylene, and combinations thereof.

In some embodiments, the non-plastic material comprises at least oneselected from the group consisting of non-plastic organic material,inorganic material, fluid, and combinations thereof.

In some embodiments, the method further comprises separating thedecomposition mixture into a solid phase and a liquid phase.

In some embodiments, the solid phase comprises at least one selectedfrom the group consisting of oligomer, polymer, and combinationsthereof.

In some embodiments, the solid phase further comprises at least onesolid state catalyst.

In some embodiments, the liquid phase comprises at least one compoundcontaining at least one carboxyl group.

In some embodiments, the at least one compound containing at least onecarboxyl group is at least one organic acid.

In some embodiments, the method further comprises converting the atleast one organic acid into at least one corresponding ester.

In some embodiments, the at least one organic acid is at least oneselected from the group consisting of a monocarboxylic acid,dicarboxylic acid, polycarboxylic acid, and combinations thereof.

In some embodiments, the at least one organic acid is anα,ω-dicarboxylic acid.

In some embodiments, the at least one organic acid is selected from thegroup consisting of succinic acid, glutaric acid, adipic acid, pimelicacid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid,dodecanedioic acid, and combinations thereof.

In some embodiments, the method further comprises separating the atleast one organic acid.

In some embodiments, the method further comprises separating the atleast one corresponding ester.

In some embodiments, the at least one solid state catalyst is selectedfrom the group consisting of zeolite, alumina, silico-alumino-phosphate,sulfated zirconia, zinc oxide, titanium oxide, zirconium oxide, niobiumoxide, iron carbonate, calcium carbide, and combinations thereof.

In some embodiments, the at least one oxidizing agent is selected fromthe group consisting of from oxygen (O₂), nitric oxide (NO), nitrousoxide (N₂O), nitrogen dioxide (NO₂), nitric acid (HNO₃), aqueous nitricacid (HNO₃), and combinations thereof.

In some embodiments, the temperature range is from 60° C. to 200° C.

In some embodiments, the gas is at least one selected from the groupconsisting of air, nitrogen (N₂), oxygen (O₂), and combinations thereof.

In some embodiments, the initial pressure of the gas is 0 psi to 1000psi.

In some embodiments, the residence time in the reaction vessel is oneselected from the group consisting of 30 minutes to 30 hours, less than30 minutes, and more than 30 hours.

In some embodiments, the method further comprises feeding the oligomer,the polymer, and combinations thereof back into the reactor.

In some embodiments, the liquid phase further comprises the at least oneoxidizing agent.

In some embodiments, the method further comprises collecting andregenerating the at least one oxidizing agent.

In some embodiments, the at least one corresponding ester is selectedfrom the group consisting of dimethyl succinate, dimethyl glutarate,dimethyl adipate, dimethyl pimelate, dimethyl suberate, dimethylazelate, dimethyl sebacate, dimethyl undecanedioate, dimethyldodecanedioate, and combinations thereof.

Some embodiments described herein relate to a composition that includessuccinic acid, glutaric acid, adipic acid, pimelic acid, and azelaicacid, or the salts or esters thereof, and at least one of oxalic acid,suberic acid, sebacic acid, undecanedioic acid, dodecanedioic acid,tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid,2-octenedioic acid, 2-nonenedioic acid, 2-decenedioic acid, and2-undecenedioic acid, or the salts or esters thereof.

In some embodiments, succinic acid is present in an amount of from about5 to about 18 wt %, glutaric acid is present in an amount of from about8 to about 28 wt %, adipic acid is present in an amount of about 10 toabout 29 wt %, pimelic acid is present in an amount of about 10 to about20 wt %, and azelaic acid is present in an amount of about 8 to about 13wt %, or an equivalent amount of the salts or esters thereof, and ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of about 9 to about 20 wt %, ifpresent sebacic acid is present in an amount of about 1 to about 10 wt%, if present undecanedioic acid is present in an amount of about 1 toabout 8 wt %, if present dodecanedioic acid is present up to about 5 wt%, if present tridecanedioic acid is present up to about 4 wt %, ifpresent tetradecanedioic acid is present up to about 2 wt %, and ifpresent pentadecanedioic acid is present up to about 0.4 wt %, or anequivalent amount of the salts or esters thereof.

In some embodiments, succinic acid is present in an amount of from about10 to about 11 wt %, glutaric acid is present in an amount of from about15 to about 18 wt %, adipic acid is present in an amount of about 16 toabout 18 wt %, pimelic acid is present in an amount of about 15 to about17 wt %, and azelaic acid is present in an amount of about 10 to about12 wt %, or an equivalent amount of the salts or esters thereof, and ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of about 13 to about 15 wt %, ifpresent sebacic acid is present in an amount of about 5 to about 9 wt %,if present undecanedioic acid is present in an amount of about 3 toabout 6 wt %, if present dodecanedioic acid is present in an amount ofabout 1 to about 3 wt %, if present tridecanedioic acid is present in anamount of about 0.5 to about 1.5 wt %, if present tetradecanedioic acidis present up to about 0.2 wt %, and if present pentadecanedioic acid ispresent up to about 0.2 wt %, or an equivalent amount of the salts oresters thereof.

In some embodiments, succinic acid is present in an amount of from about5 to about 40 wt %, glutaric acid is present in an amount of from about8 to about 27 wt %, adipic acid is present in an amount of about 10 toabout 29 wt %, pimelic acid is present in an amount of about 10 to about20 wt %, and azelaic acid is present in an amount of about 1 to about 13wt %, or an equivalent amount of the salts or esters thereof, and ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of to about 4 to about 20 wt %, ifpresent sebacic acid is present up to about 10 wt %, if presentundecanedioic acid is present up to about 8 wt %, if presentdodecanedioic acid is present up to about 5 wt %, if presenttridecanedioic acid is present up to about 4 wt %, if presenttetradecanedioic acid is present up to about 2 wt %, and if presentpentadecanedioic acid is present up to about 0.4 wt %, or an equivalentamount of the salts or esters thereof.

In some embodiments, the composition may further include at least one ofnitro-suberic acid, nitro-azelaic acid, nitro-sebacic acid,nitro-undecanedioic acid, nitro-dodecanedioic acid, nitro-brassylicacid, nitro-tetradecanedioic acid, nitro-pentadecanedioic acid,nitro-hexadecanedioic acid, nitro-heptadecanedioic acid,nitro-octadecanedioic acid, nitro-nonadecanedioic acid, ornitro-icosanedioic acid, or the salts or esters thereof. In someembodiments, the dicarboxylic acid is 2-nitro-suberic acid,2-nitro-azelaic acid, 2-nitro-sebacic acid, 2-nitro-undecanedioic acid,2-nitro-dodecanedioic acid, 2-nitro-brassylic acid,2-nitro-tetradecanedioic acid, 2-nitro-pentadecanedioic acid,2-nitro-hexadecanedioic acid, 2-nitro-heptadecanedioic acid,2-nitro-octadecanedioic acid, 2-nitro-nonadecanedioic acid, or2-nitro-icosanedioic acid, or the salts or esters thereof.

Some embodiments described herein relate to a composition that includessuccinic acid, glutaric acid, adipic acid, pimelic acid, and azelaicacid, or the salts or esters thereof, and at least one C₈-C₂₀dicarboxylic acid substituted with a single nitro group, or the salts oresters thereof.

In some embodiments, the C₈-C₂₀ dicarboxylic acid substituted with asingle nitro group may be nitro-suberic acid, nitro-azelaic acid,nitro-sebacic acid, nitro-undecanedioic acid, nitro-dodecanedioic acid,nitro-brassylic acid, nitro-tetradecanedioic acid,nitro-pentadecanedioic acid, nitro-hexadecanedioic acid,nitro-heptadecanedioic acid, nitro-octadecanedioic acid,nitro-nonadecanedioic acid, and nitro-icosanedioic acid, or the salts oresters thereof. In some embodiments, the C₈-C₂₀ dicarboxylic acid is2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid,2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, or 2-nitro-icosanedioic acid, or the saltsor esters thereof.

In some embodiments, the at least one C₈-C₂₀ dicarboxylic acidsubstituted with a single nitro group may be present up to 1 wt % in thecomposition.

In some embodiments, the composition may further include at least one ofoxalic acid, suberic acid, sebacic acid, undecanedioic acid,dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid,pentadecanedioic acid, 2-octenedioic acid, 2-nonenedioic acid,2-decenedioic acid, and 2-undecenedioic acid, or the salts or estersthereof.

In some embodiments, succinic acid may be present in an amount of fromabout 5 to about 18 wt %, glutaric acid is present in an amount of fromabout 8 to about 28 wt %, adipic acid is present in an amount of about10 to about 29 wt %, pimelic acid is present in an amount of about 10 toabout 20 wt %, and azelaic acid is present in an amount of about 8 toabout 13 wt %, or an equivalent amount of the salts or esters thereof,and if present, oxalic acid may be present in an amount up to 10 wt %,if present suberic acid is present in an amount of to about 9 to about20 wt %, if present sebacic acid is present in an amount of about 1 toabout 10 wt %, if present undecanedioic acid is present in an amount ofabout 1 to about 8 wt %, if present dodecanedioic acid is present up toabout 5 wt %, if present tridecanedioic acid is present up to about 4 wt%, if present tetradecanedioic acid is present up to about 2 wt %, andif present pentadecanedioic acid is present up to about 0.4 wt %, or anequivalent amount of the salts or esters thereof.

In some embodiments, succinic acid is present in an amount of from about10 to about 11 wt %, glutaric acid is present in an amount of from about15 to about 18 wt %, adipic acid is present in an amount of about 16 toabout 18 wt %, pimelic acid is present in an amount of about 15 to about17 wt %, and azelaic acid is present in an amount of about 10 to about12 wt %, or an equivalent amount of the salts or esters thereof, and ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of about 13 to about 15 wt %, ifpresent sebacic acid is present in an amount of about 5 to about 9 wt %,if present undecanedioic acid is present in an amount of about 3 toabout 6 wt %, if present dodecanedioic acid is present in an amount ofabout 1 to about 3 wt %, if present tridecanedioic acid is present in anamount of about 0.5 to about 1.5 wt %, if present tetradecanedioic acidis present up to about 0.2 wt %, and if present pentadecanedioic acid ispresent up to about 0.2 wt %, or an equivalent amount of the salts oresters thereof.

In some embodiments, succinic acid is present in an amount of from about5 to about 40 wt %, glutaric acid is present in an amount of from about8 to about 27 wt %, adipic acid is present in an amount of about 10 toabout 29 wt %, pimelic acid is present in an amount of about 10 to about20 wt %, and azelaic acid is present in an amount of about 1 to about 13wt %, or an equivalent amount of the salts or esters thereof, and ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of to about 4 to about 20 wt %, ifpresent sebacic acid is present up to about 10 wt %, if presentundecanedioic acid is present up to about 8 wt %, if presentdodecanedioic acid is present up to about 5 wt %, if presenttridecanedioic acid is present up to about 4 wt %, if presenttetradecanedioic acid is present up to about 2 wt %, and if presentpentadecanedioic acid is present up to about 0.4 wt %, or an equivalentamount of the salts or esters thereof.

In some embodiments, the acids may be at least partially in the form ofan alkaline metal salt.

In some embodiments, the acids may be at least partially in the form ofesters.

In some embodiments, the esters may be C₁₋₄ alkyl esters

In some embodiments, the acids may be in the form of free acids.

Some embodiments described herein relate to a method for decomposingplastic waste that includes a. adding plastic waste to a reactionvessel, b. adding aqueous nitric acid (HNO₃) to the reaction vessel togive a mixture, wherein the wt. ratio of plastic waste to aqueous nitricacid is greater than 1:3, c. subjecting the mixture obtained in b. toconditions effective to decompose the plastic waste to producedecomposition products, wherein the decomposition products includesuccinic acid, glutaric acid, adipic acid, pimelic acid, and azelaicacid, and at least one of oxalic acid, suberic acid, sebacic acid,undecanedioic acid, dodecanedioic acid, tridecanedioic acid,tetradecanedioic acid, pentadecanedioic acid, 2-octenedioic acid,2-nonenedioic acid, 2-decenedioic acid, and 2-undecenedioic acid.

Some embodiments described herein relate to a method for decomposingplastic waste, that includes a. adding plastic waste to a reactionvessel, b. adding aqueous nitric acid (HNO₃) to the reaction vessel togive a mixture, wherein the wt. ratio of plastic waste to aqueous nitricacid is greater than 1:3, c. subjecting the mixture obtained in b. toconditions effective to decompose the plastic waste to producedecomposition products, wherein the decomposition products includesuccinic acid, glutaric acid, adipic acid, pimelic acid, and azelaicacid, and at least one of C₈-C₂₀ dicarboxylic acid substituted with asingle nitro group, or the salts or esters thereof.

In some embodiments, the at least one C₈-C₂₀ dicarboxylic acidsubstituted with a single nitro group may be nitro-suberic acid,nitro-azelaic acid, nitro-sebacic acid, nitro-undecanedioic acid,nitro-dodecanedioic acid, nitro-brassylic acid, nitro-tetradecanedioicacid, nitro-pentadecanedioic acid, nitro-hexadecanedioic acid,nitro-heptadecanedioic acid, nitro-octadecanedioic acid,nitro-nonadecanedioic acid, or nitro-icosanedioic acid, or the salts oresters thereof. In some embodiments, the C₈-C₂₀ dicarboxylic acid is2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid,2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, or 2-nitro-icosanedioic acid, or the saltsor esters thereof.

In some embodiments, the at least one C₈-C₂₀ dicarboxylic acidsubstituted with a single nitro group may be present up to 1 wt % in thecomposition.

In some embodiments, the plastic waste may include polyethylene.

In some embodiments, the plastic waste further includes at least onenon-plastic waste.

In some embodiments, the nitric acid may have a concentration of 10-90wt %.

In some embodiments, the nitric acid may have a concentration of about67 to about 70 wt %.

In some embodiments, the weight ratio of plastic waste to nitric acidmay be 1:10 to 1:100.

In some embodiments, the method for decomposing plastic waste mayfurther include adding at least one solid state catalyst to the reactionvessel.

In some embodiments, the at least one solid state catalyst may be azeolite, alumina, silico-alumino-phosphate, sulfated zirconia, zincoxide, titanium oxide, zirconium oxide, niobium oxide, iron carbonate,calcium carbide, or combinations thereof.

In some embodiments, the conditions effective may include a temperaturerange of about 60° C. to about 200° C.

In some embodiments, the conditions effective may include a batchprocess with a residence time in the reaction vessel of about 1 hour toabout 10 hours.

In some embodiments, the conditions effective may include a batchprocess with a residence time in the reaction vessel of about 3 hours toabout 6 hours.

In some embodiments, the conditions effective may include a continuousprocess.

In some embodiments, the continuous process may include the continuousaddition of plastic waste and aqueous nitric acid to the reaction vesseland the continuous removal of decomposition products. In someembodiments, the plastic waste and aqueous nitric acid are continuouslyadded to the reaction vessel through a screw conveyor. In someembodiments, the decomposition products are continuously removed fromthe reaction vessel through a screw conveyor.

In some embodiments, the decomposition products include succinic acidthat is present in an amount of from about 5 to about 18 wt %, glutaricacid that is present in an amount of from about 8 to about 28 wt %,adipic acid that is present in an amount of about 10 to about 29 wt %,pimelic acid that is present in an amount of about 10 to about 20 wt %,and azelaic acid that is present in an amount of about 8 to about 13 wt%, and if present, oxalic acid is present in an amount up to 10 wt %, ifpresent suberic acid is present in an amount of about 9 to about 20 wt%, if present sebacic acid is present in an amount of about 1 to about10 wt %, if present undecanedioic acid is present in an amount of about1 to about 8 wt %, if present dodecanedioic acid is present up to about5 wt %, if present tridecanedioic acid is present up to about 4 wt %, ifpresent tetradecanedioic acid is present up to about 2 wt %, and ifpresent pentadecanedioic acid is present up to about 0.4 wt %.

In some embodiments, the decomposition produces may include succinicacid that is present in an amount of from about 10 to about 11 wt %,glutaric acid that is present in an amount of from about 15 to about 18wt %, adipic acid that is present in an amount of about 16 to about 18wt %, pimelic acid that is present in an amount of about 15 to about 17wt %, and azelaic acid that is present in an amount of about 10 to about12 wt %, and if present, oxalic acid is present in an amount up to 10 wt%, if present suberic acid is present in an amount of about 13 to about15 wt %, if present sebacic acid is present in an amount of about 5 toabout 9 wt %, if present undecanedioic acid is present in an amount ofabout 3 to about 6 wt %, if present dodecanedioic acid is present in anamount of 1-3 wt %, if present tridecanedioic acid is present in anamount of about 0.5 to about 1.5 wt %, if present tetradecanedioic acidis present up to about 0.2 wt %, and if present pentadecanedioic acid ispresent up to about 0.2 wt %.

In some embodiments, succinic acid is present in an amount of from about5 to about 40 wt %, glutaric acid is present in an amount of from about8 to about 27 wt %, adipic acid is present in an amount of about 10 toabout 29 wt %, pimelic acid is present in an amount of about 10 to about20 wt %, and azelaic acid is present in an amount of about 1 to about 13wt %, or an equivalent amount of the salts or esters thereof, and ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of to about 4 to about 20 wt %, ifpresent sebacic acid is present up to about 10 wt %, if presentundecanedioic acid is present up to about 8 wt %, if presentdodecanedioic acid is present up to about 5 wt %, if presenttridecanedioic acid is present up to about 4 wt %, if presenttetradecanedioic acid is present up to about 2 wt %, and if presentpentadecanedioic acid is present up to about 0.4 wt %, or an equivalentamount of the salts or esters thereof.

In some embodiments, the conditions effective further include thepresence of a zeolite catalyst.

In some embodiments, the method further includes isolating thedecomposition products. In some embodiments, the decomposition productsmay be isolated by removal of insoluble products. In some embodiments,the removal of insoluble products is by filtration.

In some embodiments, the method may further include evaporation ofsolvent. In some embodiments, the solvent may include nitric acid.

Some embodiments described herein relate to a method for thedecomposition of polyethylene, that includes reacting polyethylene withan oxidizing agent in a reactor to produce a reaction product and areaction gas, supplying the reaction gas to an absorption unit forrecovering the oxidizing agent from the reaction gas, and recycling theoxidizing agent from the absorption unit to the reactor.

In some embodiments, the oxidizing agent may be nitric acid.

In some embodiments, the reaction product may include a dicarboxylicacid.

In some embodiments, the reaction product may include succinic acid,glutaric acid, adipic acid, pimelic acid, and azelaic acid, or the saltsor esters thereof, and at least one of oxalic acid, suberic acid,sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioicacid, tetradecanedioic acid, pentadecanedioic acid, 2-octenedioic acid,2-nonenedioic acid, 2-decenedioic acid, and 2-undecenedioic acid, or thesalts or esters thereof.

In some embodiments, the reaction product may include at least one of2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, and 2-nitro-icosanedioic acid, or thesalts or esters thereof.

In some embodiments, the reaction product may include succinic acid,glutaric acid, adipic acid, pimelic acid, and azelaic acid, and at leastone of C₈-C₂₀ dicarboxylic acid substituted with a single nitro group,or the salts or esters thereof.

In some embodiments, the C₈-C₂₀ dicarboxylic acid substituted with asingle nitro group may be nitro-suberic acid, nitro-azelaic acid,nitro-sebacic acid, nitro-undecanedioic acid, nitro-dodecanedioic acid,nitro-brassylic acid, nitro-tetradecanedioic acid,nitro-pentadecanedioic acid, nitro-hexadecanedioic acid,nitro-heptadecanedioic acid, nitro-octadecanedioic acid,nitro-nonadecanedioic acid, or nitro-icosanedioic acid, or the salts oresters thereof. In some embodiments, the C₈-C₂₀ dicarboxylic acid is2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid,2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, or 2-nitro-icosanedioic acid, or the saltsor esters thereof.

In some embodiments, the method may further include reactingpolyethylene and the oxidizing agent with a catalyst selected from thegroup consisting of hydrochloric acid, hydrobromic acid, zinc oxide,titanium oxide, zirconium oxide, niobium oxide, zeolite, alumina,silico-alumino-phosphate, iron carbonate, calcium carbide, sulfatedzirconia, and combinations thereof.

In some embodiments, the method may further include separating thereaction product from the oxidizing agent in a separation unit. In someembodiments, the method may further include recycling the oxidizingagent recovered from the separation unit to the reactor. In someembodiments, the method may further include concentrating the oxidizingagent recovered from the separation unit prior to recycling theoxidizing agent to the reactor.

In some embodiments, the method may further include mixing the reactiongas with air, enriched air, or oxygen prior to supplying the reactiongas to the absorption unit.

In some embodiments, the polyethylene and the oxidizing agent may bereacted at a temperature of about 60° C. to about 200° C. in thereactor.

In some embodiments, a ratio of the mass of polyethylene to the mass ofoxidizing agent in the reactor may be 1:3 to 1:100. In some embodiments,the ratio of the mass of polyethylene to the mass of oxidizing agent inthe reactor may be 1:10 to 1:100.

Some embodiments described herein relate to a system for thedecomposition of polyethylene that includes a reactor configured tocarry out a reaction of polyethylene with an oxidizing agent to producea reaction product and a reaction gas, an absorption unit configured torecover the oxidizing agent from the reaction gas, and return theoxidizing agent to the reactor, and a separation unit configured toseparate the reaction product from the oxidizing agent.

In some embodiments, the separation unit may include an evaporator. Insome embodiments, the evaporator may be a wiped-film evaporator, afalling-film evaporator, a forced-circulation evaporator, or a flashevaporator.

In some embodiments, the separation unit may further include anoxidizing agent harvester.

In some embodiments, the oxidizing agent harvester may be selected fromthe group of a chromatography column, a crystallizer, a liquid-liquidextractor, and a Nutsche filter dryer.

In some embodiments, the separation unit may further include a dryer.

In some embodiments, the reactor may include a stirred tank reactor.

In some embodiments, the reactor may include a chopping blade configuredto blend and breakdown the polyethylene.

In some embodiments, the reactor may include a screw conveyor configuredto convey the polyethylene into or through the reactor.

In some embodiments, the separation unit may be configured to recyclethe separated oxidizing agent to the reactor.

In some embodiments, the system may further include a distillation unitconfigured to concentrate the oxidizing agent prior to recycling theoxidizing agent to the reactor from the absorption unit.

In some embodiments, the system may further include a condenser forcondensing the reaction gas from the reactor.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures. It isintended that the embodiments and figures disclosed herein are to beconsidered illustrative rather than restrictive.

FIG. 1 depicts, in accordance with various embodiments of the invention,a schematic diagram of a reactor system of the present invention for thedecomposition of contaminated plastic waste.

FIG. 2 depicts, in accordance with various embodiments of the invention,a chromatogram of a PE film oxidation product showing dibasic acids inthe form of esters.

FIG. 3A-FIG. 3B depict, in accordance with various embodiments of theinvention, TGA curves contrasting thermal decomposition patterns ofresin samples (FIG. 3A) to pure LDPE and waste PE film (FIG. 3B).

FIG. 4 depicts, in accordance with various embodiments of the invention,DSC curves contrasting crystalline behaviors of waste PE films and resinproduct.

FIG. 5 depicts, in accordance with various embodiments of the invention,a chemical recycling process flow diagram.

FIG. 6 depicts, in accordance with various embodiments of the invention,a continuous stirred tank reactor (CSTR) chemical recycle reactor.

FIG. 7 depicts, in accordance with various embodiments of the invention,a continuous stirred tank reactor train for chemical recycle.

FIG. 8 depicts, in accordance with various embodiments of the invention,a gravity separation reactor for chemical recycling.

FIG. 9 depicts, in accordance with various embodiments of the invention,a long-residence time plug flow reactor for chemical recycling.

FIG. 10 depicts in, accordance with various embodiments of theinvention, a screw reactor for chemical recycling.

FIG. 11 depicts, in accordance with various embodiments of theinvention, a basic separation unit for separation of solid product fromaqueous oxidizing agent.

FIG. 12 depicts, in accordance with various embodiments of theinvention, a separation unit for separation of solid product fromaqueous oxidizing agent.

FIG. 13 depicts, in accordance with various embodiments of theinvention, a separation unit with centrifugation and filtration andoxidizing agent re-introduction to the reactor.

FIG. 14 depicts, in accordance with various embodiments of theinvention, a separation unit with centrifugation and oxidizing agentre-introduction to the reactor.

FIG. 15 depicts, in accordance with various embodiments of theinvention, a separation unit without evaporation or concentration.

FIG. 16 depicts, in accordance with various embodiments of theinvention, a separation unit for direct separation to product andoxidizing agent.

FIG. 17 depicts, in accordance with various embodiments of theinvention, a separation unit with combined filtration and drying in asingle step.

FIG. 18 depicts, in accordance with various embodiments of theinvention, a basic absorption unit for reaction gas capture andconversion back into oxidizing agent.

FIG. 19 depicts, in accordance with various embodiments of theinvention, a hybrid reactor-absorption unit.

FIG. 20 depicts, in accordance with various embodiments of theinvention, a catalyst gas scrubbing reflux condenser.

FIG. 21 depicts, in accordance with various embodiments of theinvention, a flow diagram of a method to convert polyethylene into areaction product.

FIGS. 22A, B, and C depict, in accordance with various embodiments ofthe invention, a table showing the various dicarboxylic acids detectedby liquid chromatography mass spectrometry (LCMS) in a reaction product.

FIG. 23 depicts, in accordance with various embodiments of theinvention, a graph showing the analysis of methyl esters of dicarboxylicacids in a reaction product.

FIG. 24 depicts, in accordance with various embodiments of theinvention, a graph showing the yield of dicarboxylic acids at differenttemperatures.

DETAILED DESCRIPTION OF THE INVENTION

All references cited herein are incorporated by reference in theirentirety as though fully set forth. Unless otherwise defined, alltechnical and scientific terms used herein have the same meaning ascommonly understood by one of ordinary skill in the art to which thisinvention belongs.

One skilled in the art will recognize many methods and materials similaror equivalent to those described herein, which could be used in thepractice of the present invention. Other features and advantages of theinvention will become apparent from the following detailed description,taken in conjunction with the accompanying drawings, which illustrate,by way of example, various features of embodiments of the invention.Indeed, the present invention is in no way limited to the methods andmaterials described. For convenience, certain terms employed herein, inthe specification, examples and appended claims are collected here.

Unless stated otherwise, or implicit from context, the following termsand phrases include the meanings provided below. Unless explicitlystated otherwise, or apparent from context, the terms and phrases belowdo not exclude the meaning that the term or phrase has acquired in theart to which it pertains. Unless otherwise defined, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. It should be understood that this invention is not limited tothe particular methodology, protocols, and reagents, etc., describedherein and as such can vary. The definitions and terminology used hereinare provided to aid in describing particular embodiments, and are notintended to limit the claimed invention, because the scope of theinvention is limited only by the claims.

As used herein the term “comprising” or “comprises” is used in referenceto compositions, methods, systems, articles of manufacture, andrespective component(s) thereof, that are useful to an embodiment, yetopen to the inclusion of unspecified elements, whether useful or not. Itwill be understood by those within the art that, in general, terms usedherein are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). As used herein, the term “comprising” or “comprises” means thatother elements can also be present in addition to the defined elementspresented. The use of “comprising” indicates inclusion rather thanlimitation. Although the open-ended term “comprising” as a synonym ofterms such as including, containing, or having, is used herein todescribe and claim the invention, the present invention, or embodimentsthereof, may alternatively be described using alternative terms such as“consisting of” or “consisting essentially of”.

Unless stated otherwise, the terms “a” and “an” and “the” and similarreferences used in the context of describing a particular embodiment ofthe application (especially in the context of claims) can be construedto cover both the singular and the plural. The recitation of ranges ofvalues herein is merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range.Unless otherwise indicated herein, each individual value is incorporatedinto the specification as if it were individually recited herein. Allmethods described herein can be performed in any suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.The use of any and all examples, or exemplary language (for example,“such as”) provided with respect to certain embodiments herein isintended merely to better illuminate the application and does not pose alimitation on the scope of the application otherwise claimed. Theabbreviation, “e.g.” is derived from the Latin exempli gratia, and isused herein to indicate a non-limiting example. Thus, the abbreviation“e.g.” is synonymous with the term “for example.” No language in thespecification should be construed as indicating any non-claimed elementessential to the practice of the application.

Groupings of alternative elements or embodiments of the presentinvention disclosed herein are not to be construed as limitations. Eachgroup member can be referred to and claimed individually or in anycombination with other members of the group or other elements foundherein. One or more members of a group can be included in, or deletedfrom, a group for reasons of convenience and/or patentability. When anysuch inclusion or deletion occurs, the specification is herein deemed tocontain the group as modified thus fulfilling the written description ofall Markush groups used in the appended claims.

“Optional” or “optionally” means that the subsequently describedcircumstance may or may not occur, so that the description includesinstances where the circumstance occurs and instances where it does not.

As used herein, the term “substituted” refers to independent replacementof one or more (typically 1, 2, 3, 4, or 5) of the hydrogen atoms on thesubstituted moiety with substituents independently selected from thegroup of substituents listed below in the definition for “substituents”or otherwise specified. In general, a non-hydrogen substituent can beany substituent that can be bound to an atom of the given moiety that isspecified to be substituted. Examples of substituents include, but arenot limited to, acyl, acylamino, acyloxy, aldehyde, alicyclic,aliphatic, alkanesulfonamido, alkanesulfonyl, alkaryl, alkenyl, alkoxy,alkoxycarbonyl, alkyl, alkylamino, alkylcarbanoyl, alkylene, alkylidene,alkylthios, alkynyl, amide, amido, amino, amidine, aminoalkyl, aralkyl,aralkylsulfonamido, arenesulfonamido, arenesulfonyl, aromatic, aryl,arylamino, arylcarbanoyl, aryloxy, azido, carbamoyl, carbonyl, carbonylsincluding ketones, carboxy, carboxylates, CF₃, cyano (CN), cycloalkyl,cycloalkylene, ester, ether, haloalkyl, halogen, halogen, heteroaryl,heterocyclyl, hydroxy, hydroxyalkyl, imino, iminoketone, ketone,mercapto, nitro, oxaalkyl, oxo, oxoalkyl, phosphoryl (includingphosphonate and phosphinate), silyl groups, sulfonamido, sulfonyl(including sulfate, sulfamoyl and sulfonate), thiols, and ureidomoieties, each of which may optionally also be substituted orunsubstituted. In some cases, two substituents, together with thecarbon(s) to which they are attached to, can form a ring. In some cases,two or more substituents, together with the carbon(s) to which they areattached to, can form one or more rings.

Substituents may be protected as necessary and any of the protectinggroups commonly used in the art may be employed. Non-limiting examplesof protecting groups may be found, for example, in Greene and Wuts,Protective Groups in Organic Synthesis, 44^(th). Ed., Wiley & Sons,2006.

The term “carboxy” means the radical —C(O)O—. It is noted that compoundsdescribed herein containing carboxy moiety can include protectedderivatives thereof, i.e., where the oxygen is substituted with aprotecting group. Suitable protecting groups for carboxy moietiesinclude benzyl, tert-butyl, methyl, ethyl, and the like. The term“carboxyl” means —COOH.

The term “polymer” means a substance, chemical compound or mixture ofcompounds, that has a molecular structure consisting chiefly or entirelyof a large number of similar units (e.g., monomer units) bondedtogether. Of which, linear polymer is also called straight-chain becauseit consists of a long string of carbon-carbon bonds; branching polymerhas branches at irregular intervals along the polymer chain; crosslinking polymer contains branches that connect polymer chains, viacovalent, ionic, or H-bonding; optionally substituted polymer is apolymer that contains functionality at random points along thehydrocarbon chain backbone where one or more of the hydrogen atomslinked to the chain backbone may be, but are not required to besubstituted with a substituent independently selected from the group ofsubstituents provided herein in the definition for “substituents” orotherwise specified. Such polymers are said to be optionally substitutedbecause they generally do not exhibit a regular substitution patternalong the chain backbone; addition polymer is formed by adding monomersto a growing polymer chain; condensation polymer is formed when a smallmolecule condenses out during the polymerization reaction; homopolymeris formed by polymerizing a single monomer; copolymer is formed bypolymerizing more than one monomer; synthetic polymer is synthesizedthrough chemical reactions; natural polymer is originated in nature andcan be extracted; biopolymer is produced by living organisms, modifiedor natural; organic polymers are polymers that contain carbon atoms inthe backbone of the polymer chain.

The term “oligomer” means a substance, chemical compound or mixture ofcompounds that has a molecular structure consisting chiefly or entirelyof a few number of similar units (e.g., monomer units) bonded together.

The term “plastic” means a synthetic material comprising a wide range oforganic polymers such as polyolefins, polyesters, polyamides, etc., thatcan be molded into shape while soft and then set into a rigid,semi-elastic, or elastic form.

The term “about” means the recited number ±10%. For example, “about 100”means 90-110, inclusive.

Various Non-Limiting Embodiments of the Invention

It is an object of the present invention to provide methods and systemsthat provide for the decomposition of contaminated plastic waste thatovercome the limitations of known methods and systems.

Referring to FIG. 1, a reactor system for decomposing contaminated wasteplastic according to embodiments of the present invention areillustrated, where like numerals represent like parts.

Referring to FIG. 1, at least one oxidizing agent (1) and contaminatedplastic waste (2) enter Reactor 1, which is then heated to the desiredtemperature. During the reaction, the contents are agitated or stirred,and the vapors are condensed back as liquid. Gases (3) that escapethrough the condenser are channeled into an Abatement system (8) toregenerate the oxidizing agent (5). Other off gases (4) are scrubbed.The aqueous product stream (6), carrying dibasic acids, entersDistillation 1, where the oxidizing agent is distilled and collected inthe Enricher. The oxidizing agent (5) and the oxidizing agent (7) arecombined into the Enricher, which adjusts the oxidizing agent (9) to thedesired starting concentration. Close to the end of the distillation, aslurry (10) of dibasic acids and residual oxidizing agent aretransferred into Reactor 2, where methanol (11) is added for theesterification. The product stream (12), carrying dibasic esters, excessmethanol, and residual oxidizing agent, enters Distillation 2, where thethree types of outputs (13, 14, 15) are separated. In some embodimentsthe reactor system shown in FIG. 1 can be modified to accommodate batch,continuous, substantially continuous and/or semi-continuous processes.

Other useful flow schemes are contemplated via various embodiments ofthe present invention.

In various embodiments, equipment that may be used in the methods(processes) and/or systems described herein includes conventionalreactors, piping, etc. The equipment are amenable and economical for usein process plants that can be either large or small.

In various embodiments, the present invention provides a method fordecomposing contaminated plastic waste, comprising: adding contaminatedplastic waste to a first reaction vessel; adding at least one oxidizingagent to the first reaction vessel; subjecting the contaminated plasticwaste to conditions effective to decompose the contaminated plasticwaste to produce a decomposition mixture in the first reaction vessel.In some embodiments, the method further comprises producing at least onefirst off-gas. In some embodiments, the method further comprisescollecting and regenerating the oxidizing agent. In some embodiments,the method further comprises transferring the decomposition mixture to afirst distillation unit. In some embodiments, the method furthercomprises removing at least a portion of the oxidizing agent from thedecomposition mixture to form a decomposition slurry. In someembodiments, the decomposition slurry comprises at least one compoundcontaining at least one carboxyl group; and at least one residualoxidizing agent. In some embodiments, the at least one compoundcontaining at least one carboxyl group is at least one organic acid. Insome embodiments, the method further comprises transferring thedecomposition slurry to a second reaction vessel. In some embodiments,the method further comprises adding at least one alcohol to the secondreaction vessel to form an esterification reaction mixture; andsubjecting the esterification reaction mixture to conditions effectiveto form an esterification product mixture. In some embodiments, theesterification product mixture comprises at least one residual oxidizingagent, at least one alcohol, and at least one ester. In someembodiments, the method further comprises transferring theesterification product mixture to a second distillation unit. In someembodiments, the method further comprises separating the esterificationproduct mixture in the second distillation unit into a residualoxidizing agent waste stream, an ester stream, and an alcohol stream. Insome embodiments, the ester stream comprises at least one organic acidin at least one ester form. In some embodiments, the method furthercomprises adding at least one solid state catalyst to the first reactionvessel. In some embodiments, the method comprises optionally adding atleast one solid state catalyst to the first reaction vessel. In someembodiments, the method may include adding at least one solid statecatalyst to the first reaction vessel.

In various embodiments, the present invention provides a method fordecomposing contaminated plastic waste, comprising: adding contaminatedplastic waste to a reaction vessel; adding at least one oxidizing agentto the reaction vessel; and subjecting the contaminated plastic waste toconditions effective to decompose the contaminated plastic waste toproduce a decomposition mixture. In some embodiments, the method furthercomprises adding at least one solid state catalyst to the reactionvessel. In some embodiments, the method comprises optionally adding atleast one solid state catalyst to the reaction vessel. In someembodiments, the method may include adding at least one solid statecatalyst to the reaction vessel. In some embodiments, the conditionscomprise a temperature range; an initial pressure range of a gas; and aresidence time in the reaction vessel.

In various embodiments, the present invention provides a method fordecomposing contaminated plastic waste, comprising: adding contaminatedplastic waste to a reaction vessel; adding at least one oxidizing agentto the reaction vessel; optionally adding at least one solid statecatalyst to the reaction vessel; and subjecting the contaminated plasticwaste to conditions effective to decompose the contaminated plasticwaste to produce a decomposition mixture. In some embodiments, theconditions comprise a temperature range; an initial pressure range of agas; and a residence time in the reaction vessel.

In various embodiments, the present invention provides a method fordecomposing contaminated plastic waste, comprising: adding contaminatedplastic waste to a reaction vessel; adding at least one oxidizing agentto the reaction vessel; optionally adding at least one solid statecatalyst to the reaction vessel; and subjecting the contaminated plasticwaste to conditions effective to decompose the contaminated plasticwaste to produce a decomposition mixture, wherein the conditionscomprise: a temperature range; an initial pressure range of a gas; and aresidence time in the reaction vessel.

In some embodiments, the method is selected from the group consisting ofa batch process, continuous process, substantially continuous process,and semi-continuous process.

In some embodiments, the present invention provides a system fordecomposing contaminated plastic waste, comprising: a first reactionvessel; a condenser; an abatement unit; an enricher unit; a firstdistillation unit; a second reaction vessel; and a second distillationunit; wherein the first reaction vessel is connected to the condenserand to the first distillation unit; the condenser is connected to theabatement unit and to the first reaction vessel; the abatement unit isconnected to the enricher unit; the enricher unit is connected to theabatement unit; the first distillation unit is connected to the enricherunit and to the second reaction vessel; the second reaction vessel isconnected to the second distillation unit; and the second distillationunit is connected to the second reaction vessel.

Reaction Vessel

Non-limiting examples of a reaction vessel (e.g., reactors, glass linedreactors, glass flasks, containers and the like in which the methodsand/or processes of the present invention are performed) suitable foruse in a processes and/or methods of the invention are generally closed(not open to the surrounding atmosphere) and, optionally, pressurizablereactors; non-limiting types of closed, pressurizable reactors suitablefor, in particular, batch processes, continuous processes, substantiallycontinuous processes, or semi-continuous processes according to theinvention include reactors and autoclaves from Parr Instrument Company,Amar Equipments, Buchiglas, and Berghof. In some embodiments, thereaction vessel is pressurized. In some embodiments, the reaction vesselis not pressurized.

In some embodiments, the reaction vessel is at least one selected fromthe group consisting of reactor, glass flask, glass lined reactor, andcombinations thereof.

In some embodiments relevant types of reaction vessels for performingbatch processes or continuous processes, substantially continuousprocesses, or semi-continuous processes include substantially verticallydisposed reaction vessels in which the contaminated plastic waste andany additional reagents/materials (e.g. gases, liquids, solids) inquestion may be contained and into which gases may beintroduced-continuously or at intervals-under pressure or at ambientpressure via one or more inlets, ports, valves or the like situated ator near the bottom of, and/or at other locations along the length of,the reaction vessel; such reaction vessels, which may suitably, butoptionally, have an upper headspace or free volume, may be essentiallycylindrical, tubular or of any other appropriate form. In someembodiments, reaction vessels for performing batch processes orcontinuous processes, substantially continuous processes, orsemi-continuous processes include substantially horizontally disposedreactors.

In batch processes, continuous processes, substantially continuousprocesses, or semi-continuous processes it is generally desirable, wherepossible, to cause mixing of the contaminated plastic waste and anyadditional reagents/materials (e.g. gases, liquids, solids) and anysolid phase and any liquid phase and any gas phase which may be presentin the reaction vessel. In some embodiments mixing may suitably beachieved by mechanical stirring, although agitation of the reactionvessel as a whole or other means of causing mixing may be applicable. Insome embodiments, mixing may be suitably achieved by recirculation bymeans of a pump, impeller wheel, rotating scraper, or the like.

Heat may be supplied to the reaction mixture and/or reaction system(e.g., the contaminated plastic waste and any additionalreagents/materials (e.g. gases, liquids, solids) and any solid phase andany liquid phase and any gas phase which may be present in the reactor)by any suitable method. Non-limiting examples include immersing thereaction vessel in an appropriate heating bath (comprising, e, g., anoil, a molten salt or molten salt mixture, superheated steam, etc.); bymeans of thermally conductive (typically metal) tubing which is woundaround the outside of the reaction vessel, and/or is immersed in thereaction medium itself, and through which suitably hot oil, superheatedsteam or the like is passed; or-similarly-by means of one or moreelectrical resistance heating elements wound around the outside of thereaction vessel and/or immersed in the reaction medium; by a heatingmantle; or by means of a jacketed reactor as known in the art. Otherapplicable methods of heating include induction heating (e. g. of ametal reactor casing) and microwave heating.

In some embodiments, the reaction is carried out in a batch process. Inother embodiments, the reaction is carried out in a continuous process.

In a batch process, in some embodiments, oxidizing agent (e.g., nitricacid) is added to the reactor before heating and stirring begins. As thereactor reaches the desired temperature, the plastic (e.g.,polyethylene) is added and the reaction is allowed to proceed withstirring for the desired time. In some embodiments, the oxidizing agent(e.g., nitric oxide) is refluxed in the reaction vessel using acondenser during the process. After the reaction is complete, thereactor is left to cool and the reaction mixture (comprising liquid andsolid streams), are filtered, e.g., through filter paper, a sieve,Buchner funnel or the like. The solid stream comprises unreacted orincompletely reacted plastic. The liquid stream comprises dilute nitricacid, dissolved dicarboxylic acids and other compounds such asnitro-substituted dicarboxylic acids. In some embodiments, the liquidstream is then heated and the oxidizing agent (e.g., nitric acid) andwater are separated from the dicarboxylic acids by distillation.

In a continuous process, in some embodiments, the initial desired amountof oxidizing agent (e.g., nitric acid) is added to the reactor beforeheating a stirring begins. As the reactor reaches the desiredtemperature, the plastic (e.g., polyethylene) is added. The reactionvessel exit valve is then opened and adjusted so that the amount ofproduct exiting the reaction vessel is at a constant flow rate that isabout the same as the amounts of plastic and oxidizing agent being addedto the reaction vessel, thus maintaining about a constant amount ofreactants and products in the reaction vessel during the process. Insome embodiments, the oxidizing agent (e.g., nitric acid) is refluxed inthe reaction vessel using a condenser during the process. In someembodiments, samples are taking at time intervals, cooled, and filtered,e.g., through filter paper, with a sieve, Buchner funnel or the like.The liquid stream comprises dilute nitric acid, dissolved dicarboxylicacids and other compounds such as nitro-substituted dicarboxylic acids.In some embodiments, the liquid stream is then heated and the oxidizingagent (e.g., nitric acid) and water are separated from the dicarboxylicacids by distillation.

Temperature Range

In some embodiments, the temperature range is from 60° C. to 200° C. Insome embodiments, the temperature range in the reaction vessel is from60° C. to 200° C. In some embodiments, the reaction vessel is the firstreaction vessel.

In some embodiments, the temperature range is from 60° C. to 200° C.,60° C. to 175° C., 60° C. to 150° C., 60° C. to 125° C., 60° C. to 100°C., 60° C. to 90° C., 60° C. to 80° C., or 60° C. to 70° C.

In some embodiments, the temperature range is from 60° C. to 200° C.,70° C. to 200° C., 80° C. to 200° C., 90° C. to 200° C., 100° C. to 200°C., 100° C. to 200° C., 120° C. to 200° C., 130° C. to 200° C., 140° C.to 200° C., 150° C. to 200° C., 160° C. to 200° C., 170° C. to 200° C.,180° C. to 200° C., or 190° C. to 200° C.

Initial Pressure Range of a Gas

In some embodiments, the initial pressure of the gas is 0 psi to 1000psi. In some embodiments, the initial pressure of the gas in thereaction vessel is 0 psi to 1000 psi. In some embodiments, the reactionvessel is the first reaction vessel.

In some embodiments, the initial pressure of the gas is 0 psi to 900psi, 0 psi to 800 psi, 0 psi to 700 psi, 0 psi to 600 psi, 0 psi to 500psi, 0 psi to 400 psi, 0 psi to 300 psi, 0 psi to 200 psi, or 0 psi to100 psi.

Residence Time in the Reaction Vessel

In some embodiments, the residence time in the reaction vessel is oneselected from the group consisting of 30 minutes to 30 hours, less than30 minutes, and more than 30 hours. In some embodiments, the reactionvessel is the first reaction vessel.

In some embodiments the residence time in the reaction vessel is 30minutes to 30 hours, 30 minutes to 29 hours, 30 minutes to 28 hours, 30minutes to 27 hours, 30 minutes to 26 hours, 30 minutes to 25 hours, 30minutes to 24 hours, 30 minutes to 23 hours, 30 minutes to 22 hours, 30minutes to 21 hours, 30 minutes to 20 hours, 30 minutes to 19 hours, 30minutes to 18 hours, 30 minutes to 17 hours, 30 minutes to 16 hours, 30minutes to 15 hours, 30 minutes to 14 hours, 30 minutes to 13 hours, 30minutes to 12 hours, 30 minutes to 11 hours, 30 minutes to 10 hours, 30minutes to 9 hours, 30 minutes to 8 hours, 30 minutes to 7 hours, 30minutes to 6 hours, 30 minutes to 5 hours, 30 minutes to 4 hours, 30minutes to 3 hours, 30 minutes to 2 hours, or 30 minutes to 1 hour.

In some embodiments, the residence time in the reaction vessel is 30minutes, 25 minutes, 20 minutes, 15 minutes, 10 minutes, or 5 minutes.

In some embodiments, the residence time in the reaction vessel is 30hours, 35 hours, 40 hours, 45 hours, 50 hours, 55 hours, 60 hours, 65hours, 70 hours, or 75 hours. In some embodiments, the residence time inthe reaction vessel is about 1 hour to about 10 hours. In someembodiments, the residence time in the reaction vessel is about 3 hoursto about 6 hours.

In some embodiments, the reaction vessel for a batch process is Reactor1 (e.g., Reactor 1 as identified in FIG. 1). In some embodiments, thereaction vessel is a first reaction vessel. In some embodiments, thereaction vessel is Reactor 2 (e.g., Reactor 2 as identified in FIG. 1).In some embodiments, the reaction vessel is a second reaction vessel.

Effects of Time, Temperature, Pressure and Concentration

Different products and amounts of products are obtained depending on thetime, temperature and pressure of the reaction. In general, more longerchain dicarboxylic acids are obtained at shorter reaction times and lesslonger chain dicarboxylic acids are obtained at longer reaction times.Higher amounts of oxalic acid are obtained at shorter reaction times andlower reaction temperatures (e.g., at 100° C. vs. 110° C. vs. 120° C.).Mild reaction conditions give oxalic acid as the main reaction product.Oxalic acid is the major product at 100° C. with reaction times of lessthan 6 h. Oxalic acid is produced in large amounts with short reactiontimes, even with elevated temperatures. See, the Examples.

Different products and amounts of products are also obtained dependingon the concentration of nitric acid and the ratio of polyethylene tonitric acid. For example, when 70 wt % aqueous nitric acid is used asthe solvent, the product is enriched with C₄-C₉ dicarboxylic acids. With50 and 60 wt % aqueous nitric acid, the reactions are significantlyslower and the product comprises more oxalic acid and significantlyhigher amounts of C₁₀-C₁₅ dicarboxylic acids. A higher ratio of nitricacid to polyethylene gives higher amounts of C₄-C₉ dicarboxylic acidsand lower amounts of oxalic acid and longer chain dicarboxylic acids.The higher the concentration of nitric acid, the faster the reaction.The faster the reaction, the more the long chain dicarboxylic acids arebroken down into C₄-C₉ dicarboxylic acids. The amount of oxalic aciddecreases with longer reaction time and harsher conditions. See, theExamples.

Different products and amounts of products are also obtained dependingon the pressure of the reaction. At lower nitric acid concentrations andhigher pressure, a higher yield of dicarboxylic acids is obtained andcompared to reactions conducted at atmospheric pressure and highernitric acid concentrations. For example, 70 wt % aqueous nitric acid,1:10 polyethylene to nitric acid weight ratio, 6 hour reaction time,150° C., and atmospheric pressure gave a 29% dicarboxylic acid yield,while 25 wt % aqueous nitric acid, 1:10 polyethylene to nitric acidweight ratio, 6 hour reaction time, 150° C., and 500 psi pressure gave a42% dicarboxylic acid yield, with notably higher amounts of shorterchain dicarboxylic acids. See, the Examples.

Oxidizing Agent

In some embodiments, the at least one oxidizing agent is selected fromthe group consisting of oxygen (O₂), nitric oxide (NO), nitrous oxide(N₂O), nitrogen dioxide (NO₂), nitric acid (HNO₃), aqueous nitric acid(HNO₃), and combinations thereof.

In some embodiments, the aqueous nitric acid has a concentration of10%-100% by weight, 10%-90% by weight, 10%-80% by weight, 10%-70% byweight, 10%-60% by weight, 10%-50% by weight, 10%-40% by weight, 10%-30%by weight, or 10%-20% by weight.

In some embodiments, the aqueous nitric acid has a concentration of10%-100% by weight, 20%-100% by weight, 30%-100% by weight, 40%-100% byweight, 50%-100% by weight, 60%-100% by weight, 70%-100% by weight,80%-100% by weight, or 90%-100% by weight. In some embodiments, theaqueous nitric acid has a concentration of about 67 to about 70% byweight.

Solid State Catalyst

In some embodiments, the at least one solid state catalyst is selectedfrom the group consisting of zeolite, alumina, silico-alumino-phosphate,sulfated zirconia, zinc oxide, titanium oxide, zirconium oxide, niobiumoxide, iron carbonate, calcium carbide, and combinations thereof.

Contaminated Plastic Waste

In various embodiments, without limitation the plastic waste may becontaminated by non-plastic waste and may be obtained from at least oneof the following sources: municipal waste or marine debris.

The term “municipal waste”, commonly known as trash, garbage, refuse, orrubbish, refers to a waste type consisting of various items that arediscarded by the public. The composition of municipal solid waste cancomprise various waste types and can vary from municipality tomunicipality and can also change over time. In some embodimentsmunicipal solid waste can further comprise at least one other waste typesuch as biodegradable waste, recyclable materials, inert waste,electrical and electronic waste, composite wastes, contaminated plasticwaste, and combinations thereof.

The term “marine debris” refers to human created waste type that hasdeliberately or accidentally been released in a lake, river, sea, ocean,canal, or waterway. In some instances, marine debris may be mixed withnaturally occurring materials (e.g., driftwood, kelp, microorganisms,etc.). In some embodiments, marine debris comprises at least onecontaminated plastic waste.

The term “contaminated plastic waste” means any plastic and/or plasticmaterial that is used and/or produced and subsequently discarded,wherein the plastic and/or plastic material is mixed or contaminatedwith at least one non-plastic material. In various embodiments,contaminated plastic waste comprises at least one plastic material; andat least one non-plastic material. In various embodiments, contaminatedplastic waste consists of at least one plastic material; and at leastone non-plastic material. In various embodiments, contaminated plasticwaste consists essentially of at least one plastic material; and atleast one non-plastic material.

Non-limiting examples of biodegradable waste include food and kitchenwaste, green waste, paper, etc. Non-limiting examples of recyclablematerials include paper, cardboard, glass, bottles, jars, tin cans,aluminum cans, aluminum foil, metals, certain plastics, fabrics,clothes, tires, batteries, etc. Non-limiting examples of inert wasteinclude construction and demolition waste, dirt, rocks, debris, sand,concrete. Non-limiting examples of electrical and electronic wasteinclude electrical appliances, light bulbs, washing machines, TVs,computers, screens, mobile phones, alarm clocks, watches, etc.Non-limiting examples of composite wastes include waste clothing, toys,etc.

Plastic Material

In various embodiments, the plastic material comprises at least oneselected from the group consisting of plastic film, plastic foam,plastic packaging, plastic bags, plastic wrap, and combinations thereof.In some embodiments, the plastic material is at least one selected fromthe group consisting of plastic film, plastic foam, plastic packaging,plastic bags, plastic wrap, and combinations thereof.

In various embodiments, the plastic material comprises polyethylene.

In various embodiments, the plastic material comprises at least oneselected from the group consisting of polyethylene (PE), very lowdensity polyethylene, low density polyethylene (LDPE), linear lowdensity polyethylene, medium density polyethylene, cross-linkedpolyethylene, high density polyethylene (HDPE), high densitycross-linked polyethylene, high molecular weight polyethylene, ultra-lowmolecular weight polyethylene, ultra-high molecular weight polyethylene,and combinations thereof. In some embodiments, the plastic material isat least one selected from the group consisting of polyethylene, verylow density polyethylene, low density polyethylene, linear low densitypolyethylene, medium density polyethylene, cross-linked polyethylene,high density polyethylene, high density cross-linked polyethylene, highmolecular weight polyethylene, ultra-low molecular weight polyethylene,ultra-high molecular weight polyethylene, and combinations thereof.

Non Plastic Material

In the broadest sense, the non-plastic material is any material that isnot plastic or a plastic material. Non-limiting examples of non-plasticmaterials include non-plastic organic materials, inorganic materials,fluids (non-plastic fluids), etc. In various embodiments, thenon-plastic material comprises at least one selected from the groupconsisting of non-plastic organic material, inorganic material, fluid,and combinations thereof.

Non Plastic Organic Material

In some embodiments, the non-plastic organic material is at least oneselected from the group consisting of plant material, animal material,algae material, bacteria material, fungus material, virus material,biological material, cellulose material, cellulose based material,cellulose containing material, and combinations thereof.

As used herein, the term “biological material” denotes a materialoriginating, taken, isolated, derived, and/or obtained from a biologicalorganism.

In some embodiments, the non-plastic organic material is at least oneselected from the group consisting of plant derived material, animalderived material, algae derived material, bacteria derived material,fungus derived material, virus based material, biological derivedmaterial, and combinations thereof.

In some embodiments, the non-plastic organic material is at least onecellulose based material. In some embodiments, the at least onecellulose based material is at least one selected from the groupconsisting of paper-based materials, paper, paperboard, wood, engineeredwood, plant fibers, textile, fabric, and combinations thereof.

Inorganic Material

In the broadest sense, the term “inorganic material” generally meansmaterials that are not organic compounds or organic materials.Non-limiting examples of inorganic materials include rocks, minerals,glass, ceramics, metals, etc.

Fluid

Non-limiting examples of fluids include water, hydrocarbons, syntheticfluids, naturally derived fluids, acids, bases, or biological fluids, orany mixtures or combinations thereof.

In some embodiments, the fluid is at least one selected from the groupconsisting of water, hydrocarbons, synthetic fluids, naturally derivedfluids, acids, bases, biological fluids, and combinations thereof.

Non-limiting examples of water include salt water, sea water, freshwater, reclaimed water, recycled water, or waste water, or any mixturesor combinations thereof.

In some embodiments, the water is at least one selected from the groupconsisting of salt water, sea water, fresh water, reclaimed water,recycled water, waste water, and combinations thereof.

Decomposition Mixture

In various embodiments, the decomposition mixture comprises a solidphase and a liquid phase.

In various embodiments, the solid phase comprises at least one selectedfrom the group consisting of oligomer, polymer, and combinationsthereof.

In various embodiments, the solid phase further comprises at least onesolid state catalyst. In some embodiments, the solid phase optionallycomprises at least one solid state catalyst. In some embodiments, thesolid phase may include at least one solid state catalyst.

In various embodiments, the liquid phase comprises at least one compoundcomprising at least one carboxyl group. In various embodiments, theliquid phase comprises at least one compound containing at least onecarboxyl group.

In various embodiments, the at least one compound comprising at leastone carboxyl group is at least one organic acid. In various embodiments,the at least one compound containing at least one carboxyl group is atleast one organic acid.

In some embodiments, the at least one organic acid is at least oneselected from the group consisting of optionally substituted organicacid, substituted organic acid, and unsubstituted organic acid.

In some embodiments, the at least one organic acid is at least oneselected from the group consisting of monocarboxylic acid, dicarboxylicacid, polycarboxylic acid, and combinations thereof.

In some embodiments, the at least one monocarboxylic acid is at leastone selected from the group consisting of optionally substitutedmonocarboxylic acid, substituted monocarboxylic acid, unsubstitutedmonocarboxylic acid, and combinations thereof.

In some embodiments, the at least one dicarboxylic acid is at least oneselected from the group consisting of optionally substituteddicarboxylic acid, substituted dicarboxylic acid, unsubstituteddicarboxylic acid, and combinations thereof.

In some embodiments, the at least one polycarboxylic acid is at leastone selected from the group consisting of optionally substitutedpolycarboxylic acid, substituted polycarboxylic acid, unsubstitutedpolycarboxylic acid, and combinations thereof.

In some embodiments, the at least one organic acid is at least oneα,ω-dicarboxylic acid.

In some embodiments, the at least one α,ω-dicarboxylic acid is at leastone selected from the group consisting of optionally substitutedα,ω-dicarboxylic acid, substituted α,ω-dicarboxylic acid, unsubstitutedα,ω-dicarboxylic acid, and combinations thereof.

In some embodiments, the at least one organic acid is at least oneselected from the group consisting of succinic acid, glutaric acid,adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,undecanedioic acid, dodecanedioic acid, and combinations thereof.

In some embodiments, the at least one organic acid is selected from thegroup consisting of 5-50% succinic acid, 5-50% glutaric acid, 5-50%adipic acid, 5-50% pimelic acid, 0-30% suberic acid, 0-30% azelaic acid,0-20% sebacic acid, 0-10% undecanedioic acid, 0-10% dodecanedioic acid,and combinations thereof.

In some embodiments, the decomposition mixture comprises a compositioncomprising at least one selected from the group consisting of succinicacid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaicacid, sebacic acid, undecanedioic acid, dodecanedioic acid, andcombinations thereof.

In some embodiments, the decomposition mixture comprises a compositioncomprising at least one selected from the group consisting of 5-50%succinic acid, 5-50% glutaric acid, 5-50% adipic acid, 5-50% pimelicacid, 0-30% suberic acid, 0-30% azelaic acid, 0-20% sebacic acid, 0-10%undecanedioic acid, 0-10% dodecanedioic acid, and combinations thereof.

In some embodiments, the decomposition mixture comprises:

a. succinic acid, glutaric acid, adipic acid, pimelic acid, and azelaicacid, or the salts or esters thereof, and

b. at least one of oxalic acid, suberic acid, sebacic acid,undecanedioic acid, dodecanedioic acid, tridecanedioic acid,tetradecanedioic acid, pentadecanedioic acid, 2-octenedioic acid,2-nonenedioic acid, 2-decenedioic acid, and 2-undecenedioic acid, or thesalts or esters thereof.

In some embodiments,

a. succinic acid is present in an amount of from about 5 to about 18 wt%, glutaric acid is present in an amount of from about 8 to about 28 wt%, adipic acid is present in an amount of about 10 to about 29 wt %,pimelic acid is present in an amount of about 10 to about 20 wt %, andazelaic acid is present in an amount of about 8 to about 13 wt %, or anequivalent amount of the salts or esters thereof, and

b. if present, oxalic acid is present in an amount up to 10 wt %, ifpresent suberic acid is present in an amount of to about 9 to about 20wt %, if present sebacic acid is present in an amount of about 1 toabout 10 wt %, if present undecanedioic acid is present in an amount ofabout 1 to about 8 wt %, if present dodecanedioic acid is present up toabout 5 wt %, if present tridecanedioic acid is present up to about 4 wt%, if present tetradecanedioic acid is present up to about 2 wt %, andif present pentadecanedioic acid is present up to about 0.4 wt %, or anequivalent amount of the salts or esters thereof.

In some embodiments,

a. succinic acid is present in an amount of from about 10 to about 11 wt%, glutaric acid is present in an amount of from about 15 to about 18 wt%, adipic acid is present in an amount of about 16 to about 18 wt %,pimelic acid is present in an amount of about 15 to about 17 wt %, andazelaic acid is present in an amount of about 10 to about 12 wt %, or anequivalent amount of the salts or esters thereof, and

b. if present, oxalic acid is present in an amount up to 10 wt %, ifpresent suberic acid is present in an amount of about 13 to about 15 wt%, if present sebacic acid is present in an amount of about 5 to about 9wt %, if present undecanedioic acid is present in an amount of about 3to about 6 wt %, if present dodecanedioic acid is present in an amountof about 1 to about 3 wt %, if present tridecanedioic acid is present inan amount of about 0.5 to about 1.5 wt %, if present tetradecanedioicacid is present up to about 0.2 wt %, and if present pentadecanedioicacid is present up to about 0.2 wt %, or an equivalent amount of thesalts or esters thereof.

In some embodiments,

a. succinic acid is present in an amount of from about 5 to about 40 wt%, glutaric acid is present in an amount of from about 8 to about 27 wt%, adipic acid is present in an amount of about 10 to about 29 wt %,pimelic acid is present in an amount of about 10 to about 20 wt %, andazelaic acid is present in an amount of about 1 to about 13 wt %, or anequivalent amount of the salts or esters thereof, and

b. if present, oxalic acid is present in an amount up to 10 wt %, ifpresent suberic acid is present in an amount of to about 4 to about 20wt %, if present sebacic acid is present up to about 10 wt %, if presentundecanedioic acid is present up to about 8 wt %, if presentdodecanedioic acid is present up to about 5 wt %, if presenttridecanedioic acid is present up to about 4 wt %, if presenttetradecanedioic acid is present up to about 2 wt %, and if presentpentadecanedioic acid is present up to about 0.4 wt %, or an equivalentamount of the salts or esters thereof.

In some embodiments, the decomposition mixture further comprises:

c. at least one of 2-nitro-suberic acid, 2-nitro-azelaic acid,2-nitro-sebacic acid, 2-nitro-undecanedioic acid, 2-nitro-dodecanedioicacid, 2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, and 2-nitro-icosanedioic acid, or thesalts or esters thereof.

In some embodiments, the decomposition mixture comprises:

a. succinic acid, glutaric acid, adipic acid, pimelic acid, and azelaicacid, or the salts or esters thereof, and

b. at least one C₈-C₂₀ dicarboxylic acid substituted with a single nitrogroup, or the salts or esters thereof.

In some embodiments, the at least one C₈-C₂₀ dicarboxylic acidsubstituted with a single nitro group is nitro-suberic acid,nitro-azelaic acid, nitro-sebacic acid, nitro-undecanedioic acid,nitro-dodecanedioic acid, nitro-brassylic acid, nitro-tetradecanedioicacid, nitro-pentadecanedioic acid, nitro-hexadecanedioic acid,nitro-heptadecanedioic acid, nitro-octadecanedioic acid,nitro-nonadecanedioic acid, or nitro-icosanedioic acid, or the salts oresters thereof. In some embodiments, the C₈-C₂₀ dicarboxylic acid is2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid,2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, or 2-nitro-icosanedioic acid, or the saltsor esters thereof. In some embodiments, the at least one C₈-C₂₀dicarboxylic acid substituted with a single nitro group is present up to1 wt % in the decomposition mixture.

In some embodiments, the liquid phase comprises a composition comprisingat least one selected from the group consisting succinic acid, glutaricacid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacicacid, undecanedioic acid, dodecanedioic acid, and combinations thereof.

In some embodiments, the liquid phase comprises a composition comprisingat least one selected from the group consisting of 5-50% succinic acid,5-50% glutaric acid, 5-50% adipic acid, 5-50% pimelic acid, 0-30%suberic acid, 0-30% azelaic acid, 0-20% sebacic acid, 0-10%undecanedioic acid, 0-10% dodecanedioic acid, and combinations thereof.

In some embodiments, the method further comprises separating the atleast one organic acid.

Non-limiting examples of separation techniques include simpledistillation, fractional distillation, azeotropic distillation,co-distillation, fractional crystallization, standard crystallization,lyophilization, supercritical fluid extraction, solvent extraction,precipitation, and combinations thereof. In some embodiments, theseparating is carried out by at least one selected from the groupconsisting of simple distillation, fractional distillation, azeotropicdistillation, co-distillation, fractional crystallization, standardcrystallization, lyophilization, supercritical fluid extraction, solventextraction, precipitation, and combinations thereof.

Esterification

Without being bound by theory, it is hypothesized that the conversion ofat least one compound containing at least one carboxyl group (e.g., anorganic acid) from an acid form to an ester form occurs by a processcommonly known in the art as esterification. In some embodiments, theconversion of the at least one compound containing at least one carboxylgroup from an acid form to an ester form is performed underesterification conditions. In some embodiments, the dicarboxylic acidsare at least partially in the form of esters.

In some embodiments, the method further comprises converting the atleast one organic acid into at least one corresponding ester. In someembodiments, the at least one corresponding ester is at least oneselected from the group consisting of methyl ester, ethyl ester, propylester, isopropyl ester, butyl ester, isobutyl ester, sec-butyl ester,tert-butyl ester, pentyl ester, and hexyl ester, and combinationsthereof. In some embodiments, the at least one corresponding ester is amethyl ester. In some embodiments, the converting is carried out byesterification or esterifying.

In some embodiments, the method further comprises combining the at leastone organic acid with at least one alcohol to form an esterificationmixture; and subjecting the esterification mixture to conditionseffective to form at least one ester. Any suitable esterificationconditions known in the art may be used to form the at least one ester.For example, the at least one organic acid can be admixed with at leastone alcohol and the admixture heated to cause esterification. A mineralacid may be added as a catalyst.

In some embodiments, the at least one alcohol is at least one selectedfrom a group consisting of linear alcohol, branched alcohol, cyclicalcohol, and combinations thereof. In some embodiments, the at least onealcohol is at least one selected from the group consisting of methanol,ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol,tert-butanol, pentanol, hexanol, and combinations thereof. In someembodiments, the at least one alcohol is a C₁-C₁₀ alcohol. In someembodiments, the at least one alcohol is a C₁-C₄ alcohol. In someembodiments, the at least one alcohol is methanol.

In some embodiments, the at least one organic acid is independently inat least one ester form. In some embodiments, the at least one ester orester form is at least one selected from the group consisting of methylester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutylester, sec-butyl ester, tert-butyl ester, pentyl ester, and hexyl ester,and combinations thereof. In some embodiments, the at least one esterform or ester is a methyl ester.

In some embodiments, the at least one organic acid is in an ester form.In some embodiments, the α,ω-dicarboxylic acids are in an ester form. Insome embodiments the succinic acid is in an ester form. In someembodiments, the glutaric acid is in an ester form. In some embodiments,the adipic acid is in an ester form. In some embodiments, the pimelicacid is in an ester form. In some embodiments the suberic acid is in anester form. In some embodiments, the azelaic acid is in an ester form.In some embodiments, the sebacic acid is in an ester form. In someembodiments, the undecanedioic acid is in an ester form. In someembodiments, the dodecanedioic acid is in an ester form.

In some embodiments, the succinic acid, glutaric acid, adipic acid,pimelic acid, suberic acid, and azelaic acid are each independently inan ester form.

In some embodiments, the oxalic acid, suberic acid, sebacic acid,undecanedioic acid, dodecanedioic acid, tridecanedioic acid,tetradecanedioic acid, pentadecanedioic acid, 2-octenedioic acid,2-nonenedioic acid, 2-decenedioic acid, and 2-undecenedioic acid areindependently in an ester form.

In some embodiments, the 2-nitro-suberic acid, 2-nitro-azelaic acid,2-nitro-sebacic acid, 2-nitro-undecanedioic acid, 2-nitro-dodecanedioicacid, 2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, and 2-nitro-icosanedioic acid areindependently in an ester form.

In some embodiments, the C₈-C₂₀ dicarboxylic acid substituted with asingle nitro group is in an ester form. In some embodiments, the C₈-C₂₀dicarboxylic acid substituted with a single nitro group in the form ofan ester is nitro-suberic acid, nitro-azelaic acid, nitro-sebacic acid,nitro-undecanedioic acid, nitro-dodecanedioic acid, nitro-brassylicacid, nitro-tetradecanedioic acid, nitro-pentadecanedioic acid,nitro-hexadecanedioic acid, nitro-heptadecanedioic acid,nitro-octadecanedioic acid, nitro-nonadecanedioic acid, ornitro-icosanedioic acid. In some embodiments, the C₈-C₂₀ dicarboxylicacid is 2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacicacid, 2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid,2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, or 2-nitro-icosanedioic acid, or the saltsor esters thereof. In some embodiments, the ester form is selected fromthe group consisting of monoester, diester, multiester, mixed diester,mixed multiester, and combinations thereof.

The term “multiester” as used herein means an ester formed by convertingmore than one carboxyl group from an acid form to an ester form underesterification conditions.

In some embodiments, the ester form comprises a α,ω-diester, optionallysubstituted α,ω-dicarboxylic acid, or substituted α,ω-dicarboxylic acid,unsubstituted dicarboxylic acid, and combinations thereof.

In some embodiments, the at least one ester comprises dimethylsuccinate, dimethyl glutarate, dimethyl adipate, dimethyl pimelate,dimethyl suberate, dimethyl azelate, dimethyl sebacate, dimethylundecanedioate, dimethyl dodecanedioate, dimethyl oxalate, dimethyltridecanedioate, dimethyl tetradecanedioate, dimethyl pentadecanedioate,dimethyl 2-octendioate, dimethyl 2-nonendioate, 2-dimethyl2-decendioate, dimethyl 2-undecendioate, dimethyl 2-nitro-suberate,dimethyl 2-nitro-azelate, dimethyl 2-nitro-sebacate, dimethyl2-nitro-undecanedioate, dimethyl 2-nitro-dodecanedioate, dimethyl2-nitro-brassylate, dimethyl 2-nitro-heptadecanedioate, dimethyl2-nitro-octadecanedioate, dimethyl 2-nitro-tetradecanedioate, dimethyl2-nitro-pentadecanedioate, dimethyl 2-nitro-hexadecanedioate,2-nitro-heptadecanedioate, dimethyl 2-nitro-suberate, dimethyl2-nitro-sebacate, dimethyl 2-nitro-undecanedioate, dimethyl2-nitro-dodecanedioate, dimethyl 2-nitro-tetradecanedioate, and dimethyl2-nitro-pentadecanedioate and combinations thereof.

In some embodiments, the at least one corresponding ester comprisesdimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethylpimelate, dimethyl suberate, dimethyl azelate, dimethyl sebacate,dimethyl undecanedioate, dimethyl dodecanedioate, and combinationsthereof.

In some embodiments, the at least one ester comprises of 5-50% dimethylsuccinate, 5-50% dimethyl glutarate, 5-50% dimethyl adipate, 5-50%dimethyl pimelate, 0-30% dimethyl suberate, 0-30% dimethyl azelate,0-20% dimethyl sebacate, 0-10% dimethyl undecanedioate, 0-10% dimethyldodecanedioate, and combinations thereof.

In some embodiments, the at least one corresponding ester is comprisesof 5-50% dimethyl succinate, 5-50% dimethyl glutarate, 5-50% dimethyladipate, 5-50% dimethyl pimelate, 0-30% dimethyl suberate, 0-30%dimethyl azelate, 0-20% dimethyl sebacate, 0-10% dimethylundecanedioate, 0-10% dimethyl dodecanedioate, and combinations thereof.

In some embodiments, the esterification mixture comprises a compositioncomprising at least one of dimethyl succinate, dimethyl glutarate,dimethyl adipate, dimethyl pimelate, dimethyl suberate, dimethylazelate, dimethyl sebacate, dimethyl undecanedioate, dimethyldodecanedioate, and combinations thereof.

In some embodiments, the esterification mixture comprises a compositioncomprising at least one of 5-50% dimethyl succinate, 5-50% dimethylglutarate, 5-50% dimethyl adipate, 5-50% dimethyl pimelate, 0-30%dimethyl suberate, 0-30% dimethyl azelate, 0-20% dimethyl sebacate,0-10% dimethyl undecanedioate, 0-10% dimethyl dodecanedioate, andcombinations thereof.

In some embodiments, the esterification mixture comprises at least oneof dimethyl succinate in an amount of from about 5 to about 18 wt %,dimethyl glutarate in an amount of from about 8 to about 28 wt %,dimethyl adipate in an amount of about 10 to about 29 wt %, dimethylpimelate in an amount of about 10 to about 20 wt %, and dimethyl azelatein an amount of about 8 to about 13 wt %, and combinations thereof.

In some embodiments, the esterification mixture comprises at least oneof dimethyl oxalate in an amount up to 10 wt %, dimethyl suberate in anamount of about 9 to about 20 wt %, dimethyl sebacate in an amount ofabout 1 to about 10 wt %, dimethyl undecanedioate in an amount of about1 to about 8 wt %, dimethyl dodecanedioate up to about 5 wt %, dimethyltridecanedioate up to about 4 wt %, dimethyl tetradecanedioate up toabout 2 wt %, and dimethyl pentadecanedioate up to about 0.4 wt %, andcombinations thereof.

In some embodiments, the esterification mixture comprises at least oneof dimethyl succinate in an amount of from about 5 to about 40 wt %,dimethyl glutarate in an amount of from about 8 to about 27 wt %,dimethyl adipate in an amount of about 10 to about 29 wt %, dimethylpimelate in an amount of about 10 to about 20 wt %, and dimethyl azelatein an amount of about 1 to about 13 wt %, and combinations thereof.

In some embodiments, the esterification mixture comprises at least oneof dimethyl oxalate in an amount up to 10 wt %, dimethyl suberate in anamount of to about 4 to about 20 wt %, dimethyl sebacate up to about 10wt %, dimethyl undecanedioate up to about 8 wt %, dimethyldodecanedioate up to about 5 wt %, dimethyl tridecanedioate up to about4 wt %, dimethyl tetradecanedioate up to about 2 wt %, and dimethylpentadecanedioate up to about 0.4 wt %, and combinations thereof.

In some embodiments, the method further comprises separating the atleast one corresponding ester. In some embodiments, the separating iscarried out by distillation. In some embodiments, the separating of theat least one corresponding ester is carried out by distillation. In someembodiments, the distillation is at least one selected from the groupconsisting of simple distillation, fractional distillation, vacuumdistillation, azeotropic distillation, co-distillation, and combinationsthereof.

In some embodiments, the method further comprises converting the atleast one compound containing at least one carboxyl group from the esterform to an acid form (e.g., converting the ester form back to the acidform). In some embodiments, the converting of the ester form to the acidform is performed under ester hydrolysis conditions.

Salts

In some embodiments, the methods further comprise converting the atleast one dicarboxylic acid into at least one corresponding salt. Insome embodiments, the at least one corresponding salt is prepared byreacting with a base to form the ion salt of the at least onedicarboxylic acid. Bases include, but are not limited to, alkali metalsalts, alkaline earth metal salts and other metal ions. Exemplary ionsinclude aluminum, calcium, lithium, magnesium, potassium, sodium andzinc in their usual valences. Organic ions include protonated tertiaryamines and quaternary ammonium cations, including in part,trimethylamine, diethylamine, N,N′-dibenzylethylenediamine,chloroprocaine, choline, diethanolamine, ethylenediamine, meglumine(N-methylglucamine) and procaine.

In some embodiments, the dicarboxylic acids are converted into alkalinemetal salts. In some embodiments, the dicarboxylic acids are at leastpartially in the form of an alkaline metal salt. The alkaline metalsalts can be made by reacting the dicarboxylic acids with an alkalinemetal hydroxide. Exemplary alkaline metal hydroxides include sodiumhydroxide, potassium hydroxide and lithium hydroxide. Exemplary alkalinemetal salts of the dicarboxylic acids include the sodium, potassium andlithium salts.

In some embodiments, the oxalic acid, suberic acid, sebacic acid,undecanedioic acid, dodecanedioic acid, tridecanedioic acid,tetradecanedioic acid, pentadecanedioic acid, 2-octenedioic acid,2-nonenedioic acid, 2-decenedioic acid, and 2-undecenedioic acid areindependently in the form of an alkaline metal salt.

In some embodiments, the 2-nitro-suberic acid, 2-nitro-azelaic acid,2-nitro-sebacic acid, 2-nitro-undecanedioic acid, 2-nitro-dodecanedioicacid, 2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, and 2-nitro-icosanedioic acid are in theform of an alkaline metal salt.

In some embodiments, the C₈-C₂₀ dicarboxylic acid substituted with asingle nitro group is in the form of an alkaline metal salt. In someembodiments, the C₈-C₂₀ dicarboxylic acid substituted with a singlenitro group is nitro-suberic acid, nitro-azelaic acid, nitro-sebacicacid, nitro-undecanedioic acid, nitro-dodecanedioic acid,nitro-brassylic acid, nitro-tetradecanedioic acid,nitro-pentadecanedioic acid, nitro-hexadecanedioic acid,nitro-heptadecanedioic acid, nitro-octadecanedioic acid,nitro-nonadecanedioic acid, and nitro-icosanedioic acid in the form ofan alkaline metal salt. In some embodiments, the C₈-C₂₀ dicarboxylicacid is 2-nitro-suberic acid, 2-nitro-azelaicacid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid, 2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid, 2-nitro-pentadecanedioicacid, 2-nitro-hexadecanedioic acid, 2-nitro-heptadecanedioic acid,2-nitro-octadecanedioic acid, 2-nitro-nonadecanedioic acid, or2-nitro-icosanedioic acid, or the salts or esters thereof.

Some embodiments of the present invention can be defined as any of thefollowing numbered paragraphs:

1. A method for decomposing contaminated plastic waste, comprising:adding contaminated plastic waste to a reaction vessel; adding at leastone oxidizing agent to the reaction vessel; and subjecting thecontaminated plastic waste to conditions effective to decompose thecontaminated plastic waste to produce a decomposition mixture.

2. The method of paragraph 1, further comprising adding at least onesolid state catalyst to the reaction vessel.

3. The method of paragraph 1, wherein the conditions comprise atemperature range; an initial pressure range of a gas; and a residencetime in the reaction vessel.

4. The method of paragraph 1, wherein the contaminated plastic wastecomprises at least one plastic material; and at least one non-plasticmaterial.

5. The method of paragraph 4, wherein the plastic material comprises atleast one selected from the group consisting of plastic film, plasticfoam, plastic packaging, plastic bags, plastic wrap, and combinationsthereof.

6. The method of paragraph 4, wherein the plastic material comprisespolyethylene.

7. The method of paragraph 4, wherein the plastic material comprises atleast one selected from the group consisting of very low densitypolyethylene, low density polyethylene, linear low density polyethylene,medium density polyethylene, cross-linked polyethylene, high densitypolyethylene, high density cross-linked polyethylene, high molecularweight polyethylene, ultra-low molecular weight polyethylene, ultra-highmolecular weight polyethylene, and combinations thereof.

8. The method of paragraph 4, wherein the non-plastic material comprisesat least one selected from the group consisting of non-plastic organicmaterial, inorganic material, fluid, and combinations thereof.

9. The method of paragraph 1, further comprising separating thedecomposition mixture into a solid phase and a liquid phase.

10. The method of paragraph 9, wherein the solid phase comprises atleast one selected from the group consisting of oligomer, polymer, andcombinations thereof.

11. The method of paragraph 10, wherein the solid phase furthercomprises at least one solid state catalyst.

12. The method of paragraph 9, wherein the liquid phase comprises atleast one compound containing at least one carboxyl group.

13. The method of paragraph 12, wherein the at least one compoundcontaining at least one carboxyl group is at least one organic acid.

14. The method of paragraph 13, further comprising converting the atleast one organic acid into at least one corresponding ester.

15. The method of paragraph 13, wherein the at least one organic acid isselected from the group consisting of monocarboxylic acid, dicarboxylicacid, polycarboxylic acid, and combinations thereof.

16. The method of paragraph 13, wherein the at least one organic acid isan α,ω-dicarboxylic acid.

17. The method of paragraph 13, wherein the at least one organic acid isselected from the group consisting of succinic acid, glutaric acid,adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,undecanedioic acid, dodecanedioic acid, and combinations thereof.

18. The method of paragraph 13, further comprising separating the atleast one organic acid.

19. The method of paragraph 14, further comprising separating the atleast one corresponding ester.

20. The method of paragraph 2, wherein the at least one solid statecatalyst is selected from the group consisting of zeolite, alumina,silico-alumino-phosphate, sulfated zirconia, zinc oxide, titanium oxide,zirconium oxide, niobium oxide, iron carbonate, calcium carbide, andcombinations thereof.

21. The method of paragraph 1, wherein the at least one oxidizing agentis selected from the group consisting of oxygen (O₂), nitric oxide (NO),nitrous oxide (N₂O), nitrogen dioxide (NO₂), nitric acid (HNO₃), aqueousnitric acid (HNO₃), and combinations thereof.

22. The method of paragraph 3, wherein the temperature range is from 60°C. to 200° C.

23. The method of paragraph 3, wherein the gas is at least one selectedfrom the group consisting of air, nitrogen (N2), oxygen (O2), andcombinations thereof.

24. The method of paragraph 3, wherein the initial pressure of the gasis 0 psi to 1000 psi.

25. The method of paragraph 3, wherein the residence time in thereaction vessel is one selected from the group consisting of 30 minutesto 30 hours, less than 30 minutes, and more than 30 hours.

26. The method of paragraph 10, further comprising feeding the oligomer,the polymer, and combinations thereof back into the reactor.

27. The method of paragraph 9, wherein the liquid phase furthercomprises the at least one oxidizing agent.

28. The method of paragraph 27, further comprising collecting andregenerating the at least one oxidizing agent.

29. The method of paragraph 11, wherein the at least one solid statecatalyst is selected from the group consisting of zeolite, alumina,silico-alumino-phosphate, sulfated zirconia, zinc oxide, titanium oxide,zirconium oxide, niobium oxide, iron carbonate, calcium carbide, andcombinations thereof.

30. The method of paragraph 14, wherein the at least one correspondingester is selected from the group consisting of dimethyl succinate,dimethyl glutarate, dimethyl adipate, dimethyl pimelate, dimethylsuberate, dimethyl azelate, dimethyl sebacate, dimethyl undecanedioate,dimethyl dodecanedioate, and combinations thereof.

Some embodiments described herein relate to a system that combinesPolyethylene (definition provided at the end of the document) with anOxidizing Agent (definition provided at the end of the document) in areactor to break-down polyethylene into Product (definition provided atthe end of the document) and recycle the Oxidizing Agent. The system iscomprised of multiple units and to attain high conversion ofpolyethylene, low waste production, and minimize the makeup of OxidizingAgent. In addition to the Oxidizing Agent, a catalyst (definitionprovided at the end of the document) may be used in the process toenhance the reaction rate or product yield. The main components of thesystem include a reactor, Reaction Gas (definition provided at the endof the document) recovery and regeneration unit, Product recovery unit,and an Oxidizing Agent concentration unit. This process can be run inmultiple modes of operation: batch, semi-batch, and continuous. Thelayout of the process will be different depending on the mode ofoperation.

This disclosure defines the complete polyethylene chemical recyclingsystem that currently does not exist commercially. The chemicalrecycling process disclosed herein is unique and addresses a hugeplastic waste problem by diverting polyethylene from landfills. Thisprocess transforms polyethylene to Product that can be used forvalue-adding industrial applications (e.g., performance materials,polymers, fibers, compostable plastics, paints and coatings, lubricants,adhesives, fragrances, skincare products, etc.) serving as a drop-inreplacement of existing chemical intermediates, or as new chemicalintermediates.

In the existing literature, there have been attempts to convertpolyethylene into chemical compounds such as dicarboxylic acids. Piferet al. (“Chemical Recycling of Plastics to Useful Organic Compounds byOxidative Degradation,”Angewandte Chemie International Edition, Vol. 37,Issue 23; pp. 3306-3308, 1998) as well as Remias et al. (“OxidativeChemical Recycling of Polyethene,” Comptes Rendus de lAcadémie desSciences—Series IIC—Chemistry, Vol. 3, Issue 7; pp. 627-629, 2000) haveconverted low density and high density polyethylene into valuablechemicals including succinic acid, glutaric acid, adipic acid, andpimelic acid. However, such methods involve using reactive gases (i.e.nitric oxide) in pressurized autoclaves and suggest scale-up challengesdue to high operating and capital expenses. The system and methoddisclosed herein is able to produce valuable chemicals, such as thedicarboxylic acids mentioned above, from polyethylene using refluxmethods with industrially common Oxidizing Agent (e.g., nitric acid).Although Garaeva et al. (“Composition, Properties, and Application ofProducts Formed in Oxidation of Polyethylene by Nitric Acid,” RussianJournal of Applied Chemistry, Vol. 83, Issue 1; pp. 97-101, 2010) hasattempted nitric acid reflux with polyethylene, the research groupproduced a majority output of nitrocarboxylic acids, which are lessvaluable and have fewer industrial applications compared to thenon-nitrated dicarboxylic acids such as those capable of being producedas disclosed herein.

In this disclosure, polyethylene is a polymer with many repeating carbonunits that is continually broken down into shorter segments andfunctionalized (e.g., carbon chains can become oxidized formingdicarboxylic acids or monocarboxylic acids). The scission eventcontinues as long-chain polymers depolymerize into graduallyshorter-chain species by the Oxidizing Agent until the chain-length hasreached a terminal length range and is no longer broken down (e.g.,C2-C9 dicarboxylic acids). Alternatively, the reaction process can becontrolled to stop the scission event prematurely to achieve chainlengths that are longer than the terminal length range. These variouschain lengths are collectively considered Product. To enable thereaction of polyethylene into Product, an appropriate amount ofOxidizing Agent is added to breakdown the polymer into desired chainlengths and the Oxidizing Agent should be at an appropriateconcentration as well as Polyethylene-to-Oxidizing Agent ratio toproduce Product quantities large enough for commercial application. Theprocesses and equipment described in this disclosure allow for controlover the process to enable conversion of polyethylene into Product,including terminal reaction species and/or other species of desiredchain-lengths.

Both the overall process and individual units are optimized toeconomically convert polyethylene to Product and minimize use ofOxidizing Agent and Catalyst. The equipment for chemical recycling ofpolyethylene is designed to optimize process performance metrics withinthat unit (e.g., the reactor is designed to maximize conversion ofpolyethylene, the separation units are designed to recover OxidizingAgent and recycle back to the reactor, and the absorption unit torecover Reaction Gas and regenerate the Oxidizing Agent). These unitsare designed to minimize energy use and are combined into a processsystem that recovers and re-uses Oxidizing Agent and Catalyst tominimize the amount made-up in the process. This process is alsodesigned to minimize waste in the gas and liquid phases. Overall, thisprocess can significantly improve the economics of producing Productwhile diverting polyethylene from waste streams (e.g., landfill and theocean), extending the lifetime of the carbon. In addition, use ofpolyethylene for Product reduces the use of petrochemical feedstock thatis conventionally used to make Product.

Method to Convert Polyethylene Into a Reaction Product

Disclosed herein is a method/process to convert polyethylene into areaction product, or “product,” using an Oxidizing Agent and specificoperating conditions (e.g., temperatures between 60° C. and 200° C.).This is a chemical reaction that is controlled in a reactor. The problemis that the Oxidizing Agent is partially converted into a Reaction Gasthat exits the reactor in the gas phase. To make the process economical,this Reaction Gas is converted back into the Oxidizing Agent andrecycled to the reactor. The Product and Oxidizing Agent that remain inthe liquid phase are removed from the reactor and the Product isseparated. This disclosure details solutions to separate, recover, andrecycle the Oxidizing Agent as well as recover the Product.

In an embodiment of a method for decomposition of polyethylene 500 asshown in FIG. 21, polyethylene and an oxidizing agent are supplied toand react in a reactor to produce a reaction gas and a reaction product510. The reaction gas is supplied to an absorption unit to recoveroxidizing agent from the reaction gas 520. The recovered oxidizing agentfrom the absorption unit is then recycled to the reactor 530 in order toimprove the economics of the decomposition process. The reaction productmay be supplied to a separation unit for separating the product andoxidizing agent. The oxidizing agent recovered from the separation unitmay also be recycled to the reactor.

System that Uses an Oxidizing Agent to Break-Down Polyethylene IntoProduct and Recycles the Oxidizing Agent

A simplified illustration of the process flow 100 for a chemicalrecycling process is shown in FIG. 5. The main process to produceProducts, consists of four key units: the reactor (React.) 120,Oxidizing Agent regeneration in an absorption unit (Abs.) 140,Product/Oxidizing Agent separation unit 160 to separate the OxidizingAgent and Product (Evap) into two separate streams, and then a unit 170to concentrate the Oxidizing Agent back to concentrations necessary forthe reactor 120, enabling recycle. The chemical reactor 120 breaks downpolyethylene into Product. Key metrics for the reaction are the relativeamounts of the polyethylene to Oxidizing Agent fed into the reactor 120,the concentration of Oxidizing Agent in the aqueous phase, and the otherprocess variables like pressure, temperature, mixing, and residencetime. In addition, a catalyst may be fed into the reactor 120 to speedthe conversion of polyethylene into Product. The relative amount ofpolyethylene in mass to Oxidizing Agent in mass added into the reactor120 as well as the concentration of Oxidizing Agent dictates thereaction rates and polyethylene conversion to Product and also the typeof chemical reactor used. For a stirred tank reactor, the amount ofpolyethylene to Oxidizing Agent on a mass basis may be in the range of(e.g., 1:3 to 1:100, e.g., 1:10 to 1:100, e.g., 1:3 to 1:50, e.g., 1:3to 1:25, e.g., 1:3 to 10, e.g. 1:3 to 1:5).

In FIG. 5, the reactor section 121 of the process is highlighted andwithin the box with a dashed-line. Two feed streams labeled 1 and 2contain the polyethylene and Oxidizing Agent, respectively. Manydifferent reactor types, geometries, and configurations are possible aswell as how the feed streams are added into the reactor. Once in thereactor 120, the polyethylene and Oxidizing Agent react at elevatedtemperatures (e.g., 60° C. to 200° C., e.g., 75° C. to 150° C., e.g.,100° C. to 125° C.), producing a Reaction Gas. The Reaction Gas as wellas volatilized Oxidizing Agent and entrained liquid/solid droplets willexit the top of the reactor 120 [stream 3] and can enter either into acondenser unit (Cond.) 150 or directly into the absorption unit 140. Thepurpose of the condenser unit 150 is to condense any volatilized liquidsif the process is run around the boiling point of the Oxidizing Agent(e.g., any boiled off liquid vapors will be cooled in the condenser andsent back to the reactor) [stream 7]. The non-condensable gases willcontinue to the feed of the absorption unit 140 [stream 8]. Theabsorption unit 140 will be designed to convert any Reaction Gas backinto the Oxidizing Agent. An intermediate step will be to fully oxidizethe Reaction Gas using air, enriched oxygen, or pure oxygen (e.g.,converting NO to NO₂). The air, enriched oxygen, or pure oxygen streamwill be fed into the absorption unit 140 or mixed with the Reaction Gas[stream 8] prior to being fed into the absorption unit 140. It is alsopossible that air or enriched oxygen is added directly into the reactor120. The Reaction Gas that can be regenerated directly back into theOxidizing Agent flows up the absorption column that is packed withdifferent internal structured materials or trays, contacting a liquidphase that is fed into the top of the absorption column [stream 15]. TheReaction Gas absorbs into the liquid phase (e.g., NO, NO₂, N₂O₃, N₂O₄absorbs into water), reacting and converting back into the OxidizingAgent (e.g., HNO₃). This recovered and regenerated Oxidizing Agent instream 9 can be sent directly back to the reactor 120 or sent to theunit 170 used to concentrate the Oxidizing Agent (e.g., mixed withstream 18). The gas exiting the absorption unit [stream 12] will containvery small amounts of the Reaction Gas and can be emitted to theatmosphere or sent to additional units to remove any VOCs or to furtherreduce the Reaction Gas concentration.

At the bottom of the reactor 120, liquid is withdrawn [stream 4] and canbe sent directly to the separation section (Evap.) 160 to separateProduct (e.g., 1 wt % to 20 wt % dicarboxylic acid) from the OxidizingAgent or sent to other units prior to the separation (like aliquid-liquid separator 130 or another reactor). The case of having anintermediate liquid-liquid separation unit (L/L Sep.) 130 prior to theseparation unit 160 is shown in FIG. 5. The purpose of the liquid-liquidseparation unit 130 is to enable recycling of the separate phase ofunreacted or partially reacted polyethylene that is either a solid orliquid. The liquid-liquid separation unit 130 could be a vessel that isdesigned to let two or more different density phases separate and thenremove each of the phases individually (e.g., the low-density phase isremoved from the top of the vessel and the high-density phase is removedfrom the bottom of the vessel). The unreacted or partially reactedpolyethylene [stream 5] will be recycled back to the reactor [stream 13]or sent in stream 14 to another unit or purged from the system toprevent buildup of any inert or species that do not react. Theliquid-liquid separation unit 130 may be a separator vessel, acentrifugal type device (cyclone or hydrocyclone), a mechanical devicelike a continuous flow centrifuge, among others. The liquid-liquidseparation unit 130 may also incorporate filtration to remove any solidsor additional modifications to handle solids that may come into theprocess in the form of contamination on the polyethylene (e.g., theseparation vessel may be designed for three or more phases (gas,low-density liquid, high-density liquid, and high-density solids).

The product stream from the reactor 120 and liquid-liquid separationunit [stream 6] primarily contains Product and Oxidizing Agent. Thisstream is sent to the separation unit (Evap.) 160 to separate theProduct from the Oxidizing Agent. This can be done in single or multiplesteps and using different physical principles. For example, stream 6could be sent to an evaporator where the Oxidizing Agent is vaporized[stream 18] and the Product [stream 19] remains a liquid, takingadvantage of the different boiling points of the species. The type ofevaporator could be a wiped-film evaporator, falling-film evaporator,forced-circulation evaporator or a flash evaporator, for example. Thedegree of separation may vary. In one case, all of the low boilingmaterial is removed causing the Product to form a solid (e.g. allOxidizing Agent is removed), recovering nearly all of the OxidizingAgent. This would improve the overall economics and may simplify Productstorage and transportation. Examples of types of equipment that allowfor complete removal of all Product into solid-form from stream 6:

1. hybrid wiped-film evaporator with internals to prevent solid buildupand to convey solids out of the equipment like a screw conveyor, and

2. spray dryer where all of the volatile liquid and active-OxidizingAgent is evaporated. This may also include the option where part of thevolatile liquid in stream 6 is removed in equipment discussed above,concentrating the product stream (e.g., 25-90% of the volatile liquid instream 6 is removed) and then the concentrated product stream is sent toa spray dryer, or fluidized bed dryer, or rotary drum dryer) where theremaining liquid is removed.

The separation unit 160 could also be a crystallizer, where the productsare solidified and removed via filtration or some other technique. Theseparation unit 160 could also be an extraction unit where stream 18 iscontacted with another liquid that the Product is soluble in, but thatthe Oxidizing Agent is insoluble.

The vaporized or separated Oxidizing Agent stream out of the separationunit 160 [stream 18] may be recycled directly to the reactor 120 (e.g.,connected and mixed with streams 21 or 10) or the Oxidizing Agent mayneed to be concentrated in a separate unit. This unit could be adistillation unit (Dist.) 170 where the aqueous phase is partiallyseparated from the Oxidizing Agent and removed [stream 17],concentrating the Oxidizing Agent to a concentration necessary to berecycled to the reactor 120 (e.g., 45 wt % to 95 wt %, e.g., 50 wt % to75 wt %) [stream 16]. This concentrating section may be a distillationcolumn with different internals or packing, or a rectifying column thatthis attached the top of evaporation unit where the vapor stream 18would be the feed. The feed into the distillation unit 170 may be a mixof any number of streams into the process where the Oxidizing Agentconcentration of the mixed stream is less than what is needed for thereactor 120. Stream 16 out of the distillation column 170 or OxidizingAgent concentrator may flow at a rate necessary to supply all OxidizingAgent to the reactor 120 (e.g. 1 to 50 times the rate of thepolyethylene feed) or partially supply Oxidizing Agent to the reactor120, in which case additional Oxidizing Agent is added to the process[stream 2]. In addition, a dilute makeup Oxidizing Agent stream may besent to the distillation unit 170 to offer more options for process feedand potentially reduce costs (e.g., [stream 2] is a dilute OxidizingAgent that is mixed with [stream 18] instead of being directly fed tothe reactor). In this scenario, the distillation column 170 orconcentration unit supplies all oxidizing agent to the reactor 120.

An example of the overall process considers the process configuration,which is one of many. This example illustrates the importance of eachstep and how when combined, creates an efficient complete process. Thebasis considered for this example is 1000 kg/hr of feed polyethylene anda ratio of 1:20 for the amount of polyethylene to Oxidizing Agent fedinto the reactor 120 (the amount of Oxidizing Agent fed into the reactorincludes recycle and make-up, which may be 20,000 kg/hr). For a singlestirred tank reactor, polyethylene is added into the system as well asOxidizing Agent. The polyethylene and Oxidizing Agent react formingProduct and Reaction Gas. In this example, polyethylene is 100%converted into Product by mass (the relative fraction of dicarboxylicacids to other species is 80%). Oxidizing Agent reacts with Polyethyleneand 15 wt % of the Oxidizing Agent converts into Reaction Gas andProduct (alternatively, for every mole of Oxidizing Agent reacted a moleof Reaction Gas is produced). The product and unreacted Oxidizing Agentstream exits the bottom of the reactor 120 and is fed to a first unit(e.g., evaporator) to separate Oxidizing Agent and Product. In thisunit, 92 wt % of the stream is vaporized and all of the Product and someof the Oxidizing Agent exit the bottom of the unit (e.g., about 5 w% to20 wt % of this stream is Oxidizing Agent) and may continue for furtherprocessing to purify the Product and remove any residual Oxidizing Agent(e.g., separate dicarboxylic acids from other species or separatedicarboxylic acids into individual species). The vapor stream out of thefirst unit (e.g., evaporator) is primarily Oxidizing Agent at aconcentration lower (e.g., 55 wt % to 63 wt %) than the specified feedOxidizing Agent concentration (e.g., 65 wt % to 70 wt %), because afraction of the Oxidizing Agent has reacted and converted to ReactionGas and Product. The vapor is sent to another separation unit (e.g.,distillation column, or addition tank) to concentrate the OxidizingAgent (e.g., remove water from an aqueous Oxidizing Agent, or add higherconcentrations of the Oxidizing Agent) to the desired startingconcentration. This recovered Oxidizing Agent is recycled back to thereactor 120 and makes up ˜85% of the Oxidizing Agent added into thereactor 120 as Oxidizing Agent feed. At the top of the reactor 120, theReaction Gas is mixed with air to oxidize some of the Reaction Gas(e.g., convert NO into NO₂). The Reaction Gas stream is then sent to anabsorption column 140 to react the Reaction Gas with water and convertinto Oxidizing Agent (e.g., the Reaction Gas is contacted with water toproduce Oxidizing Agent). The regenerated Oxidizing Agent is recycledback to the reactor 120 and the tail gas exiting the absorption column140 is mostly N₂ (e.g., ˜95%). Recovering and recycling the OxidizingAgent from the reactor bottoms separated from the Product andconcentrated and the Oxidizing Agent regenerated from the Reaction Gas,results in >97.5 wt % Oxidizing Agent recovery, requiring only a smallmakeup Oxidizing Agent stream. This overall process example highlightshow different process units integrate to enable efficient conversion ofpolyethylene to Product, minimizing waste and the need to consumeOxidizing Agent, reducing operating costs of the process.

The process may have multiple reactor units 120, different types ofreactor units, and different sizes of reactor units. The reactor units120 may be in series or parallel configuration with heating, cooling, ordifferent types of equipment between the reactor units (likeliquid-liquid separators to separate any polyethylene from Product thatis not fully reacted). The process may be operated in batch, semi-batch,or continuous mode. Different sections may be operated in differentmodes. For example, multiple reactors connected in parallel may beindividually operated in batch mode. The reactor process is staggered sothat one reactor is always being emptied and supplies other parts of theprocess. After emptying, that reactor is filled again and anotherreactor that has completed the process is emptied.

The piping layout connecting the process equipment and how the streamsare mixed and added into each unit can be varied. The flow rates, thepressure, temperature, and Reynolds number of the fluid in the pipe mayvary as well as varying the, size and materials of the piping and lines.

The layout and construction of the system maybe an entirely new plant(green field), built on an existing plant site (brownfield), a retro-fitof a process that has some applicable existing process equipment, astick-build plant, a single modular plant, a modular plant where eatunit is a separate module.

Reactor for Converting Polyethylene Into Product

A reactor 120 is used to convert polyethylene into product. The chemicalreaction involved in this conversion happens in the chemical reactormentioned in this disclosure.

An embodiment includes a reactor 120 as a component of the whole processand uses an Oxidizing Agent to convert polyethylene into chemicalProduct and generate Reaction Gas. The reactor 120 can be a continuousstirred tank reactor, semi-continuous reactor, or batch reactor withcontrolled heating, agitation to mix the reactor content, reflux tocondense the vapors, control valve to control the flow of product streamfrom reactor to separation unit, and feeder unit that feeds the inputsat a uniform rate. There may also be multiple reactor vessels to enablestaged reactions.

Generally, pretreated or untreated polyethylene enters the reactor 120along with Oxidizing Agent (e.g., 45 wt % to 95 wt % nitric acid). Thispretreatment involves one or more of the unit operations includingshredding, cleaning, pulverizing, melting, washing and drying. Thereactor 120 is designed to handle different forms of polyethylene andcan be operated with variable temperature, stirring and flowrate of themixture. As the reactor 120 reaches desired temperature (e.g.temperatures between 60° C. and 200° C., e.g., 80° C. to 150° C.), theconversion reaction starts. Near the start of the reaction, OxidizingAgent will enable the polyethylene to be depolymerized intoshorter-chain species, and as the reaction proceeds, these shorter-chainspecies will be further broken down into Product. A Reaction Gas will begenerated. Any unreacted polyethylene or shorter-chain species can befurther reacted into Product.

FIG. 6 shows a stirred tank reactor that can be operated in batch,semi-batch or continuous mode (in one embodiment, continuous mode). Thisreactor 120 has multiple ports to add and remove material from thereactor 120 (e.g., feed, recycle, outlets, etc.). The Oxidizing Agent isadded into the reactor 120 at a specified concentration through arecycle stream 122 or make-up feed stream or both. Polyethylene is addedseparately into the reactor 120, but the make-up Oxidizing Agent couldbe combined with the polyethylene to create a dispersion that is fedinto the reactor 120. The reactor 120 can include a system 124 to addthe polyethylene into the reactor 120 such as a screw conveyor ormelting of the polyethylene and extruding the liquid polyethylene intothe reactor. The form factor and size of the polyethylene is importantto the process as well. The smaller the polyethylene size the moreexposed surface area of the dispersed or emulsified polyethylene thereis per unit volume of the polyethylene that is exposed to the OxidizingAgent, resulting in a faster reaction. The tank will be stirred andcapable of creating high turbulence and shear rates to disperse thepolyethylene and Oxidizing Agent and also mix the Oxidizing Agent andpolyethylene. Different types of impellers 126 may be used (e.g.,paddle, anchor, helical, propeller, pitched blade, etc.). There may bean additional feature at the bottom of the reactor where a motor drivesa chopping blade 128 within the reactor 120. The chopping blade 128 actsto blend and breakdown the polyethylene even further using very highrotation rates, creating very high shear like in a blender (e.g.,rotating at 500 to 10,000 rpm). This chopping blade 128 may be used inlieu of feeding a pre-treated polyethylene or in combination. Thereactor 120 may also have different geometries and features. This mayinclude a boot at the bottom to separate the Oxidizing Agent phase fromthe fresh or incompletely reacted polyethylene phase to enable a productstream that is entirely or mostly the Oxidizing Agent and Product. Thereactor vessel may have different size and geometries, but the size isprimarily determined from the desired residence time in the reactor(e.g., 30 min to 12 hr, e.g., lhr to 9 hr, e.g., 1 hr to 5 hr, e.g., 3hr to 9 hr, e.g., 3 hr to 5 hr). The residence time may vary dependingon the process conditions (e.g., higher temperature may require ashorter residence time). The residence time is scale independent and isdetermined from the mass of material in the reactor divided by the flowrate of the combined feed streams into the reactor.

For example, one metric ton of polyethylene per hour is added into thereactor 120. The ratio of polyethylene to Oxidizing Agent is 1:100,making the combined Oxidizing Agent recycle and make-up mass flow 100metric tons per hour. For a residence time of 3 hours, the requiredreactor capacity is 3 hrs×101 metric tons/hour or 303 metric tons. Toprocess the same polyethylene feed rate, a concentrated feed ratio of1:10 would require the feed stream flows of one metric ton ofpolyethylene per hour and a combined Oxidizing Agent recycle and make-upmass flow of 10 metric tons per hour. The reactor capacity for a 3 hourresidence time is only 33 metric tons. An even more concentrated feedratio of 1:3 would require the feed stream flows of one metric ton ofpolyethylene per hour and a combined Oxidizing Agent recycle and make-upmass flow of 3 metric tons per hour. The reactor capacity for a 3 hourresidence time is only 12 metric tons. Higher ratios of polyethylene toOxidizing Agent are preferable to reduce the reactor size and volume.But higher ratios of polyethylene to Oxidizing Agent may requiredifferent residence times (e.g. 3-12 hrs, e.g., 3-9 hrs, e.g., 3-5 hrs)and Oxidizing Agent concentrations in a single reactor or multiplereactors to allow for replenishment of the Oxidizing Agent to increasethe Oxidizing Agent concentration and speed the breakdown ofpolyethylene.

FIG. 7 shows a reactor scheme used to promote complete conversion of thepolyethylene into Product. This scheme shows multiple stirred tankreactors 120 in series where the effluent from one reactor 120 feedsinto a next reactor 120. There is a capability to add fresh OxidizingAgent at a specified concentration to the feed of the next reactor 120that will increase the concentration of the Oxidizing Agent in the tankonce mixed. The number of stirred tanks can be influenced by therelative amount of polyethylene to Oxidizing Agent phase in the firstreactor. The more polyethylene added into the system, the more reactorsmay be required as well as the need to add more Oxidizing Agent tomaintain a high reaction rate. In this multiple reactor scheme, stirredtanks and plug flow reactors may be alternated (e.g., a plug flowreactor is followed by a stirred tank and vice versa).

FIG. 8 shows a gravity flow reactor 220 that is a tall vessel maintainedat the specified temperature and pressure. The Oxidizing Agent phase isadded to the top of the reactor vessel and flows down the reactor 220.The polyethylene is added to the bottom of the reactor vessel by addingsolid polyethylene or melting polyethylene and extruding thepolyethylene into the vessel in a liquid form. Because the polyethyleneis lower density than the Oxidizing Agent phase, the polyethylene (insolid or liquid state) will rise up the reactor 220 if the solidparticle or liquid droplet velocity is larger than the downward velocityof the aqueous fluid. As the particles or droplets rise up the reactor220, they react with the Oxidizing Agent. The concentration of theOxidizing Agent is lowest at the bottom of the reactor 220 and increasestoward the top where fresh “high-concentration” Oxidizing Agent isadded. As the solid particles or liquid droplets rise up the reactor 220they react and the diameter decreases. In addition, as they rise, theOxidizing Agent concentration increases, increasing the rate, consumingmore polyethylene and further reducing the diameter. Thiscounter-current flow reactor maximizes the reaction driving forcethroughout the reactor. The Product is removed from the bottom of thereactor 220 and any unreacted polyethylene and Reaction Gas is separatedand removed separately. Unreacted polyethylene or partially reactedpolyethylene can be removed or recycled back to the reactor 220.Additionally, Oxidizing Agent at a specified concentration can be addedat different locations within the reactor 220 to increase the OxidizingAgent concentration.

FIG. 9 shows a plug flow reactor 320. Polyethylene and Oxidizing Agentare pumped into a tube 322 where the temperature and pressure arecontrolled. As the mixture is heated and mixed through turbulence, thepolyethylene and Oxidizing Agent react. The mixing may be augmented byusing static mixers or other inline mixers 324. The diameter and lengthof the reactor tube 322 is chosen to meet a specific residence time andalso the fluid flow regime. As the fluid mixture moves down the reactor320 the polyethylene and Oxidizing Agent continue to react. Pumps andknock-out vessels can be added periodically to move the fluid and alsoremove any Reaction Gas. Additionally, Oxidizing Agent at a specifiedconcentration can be added at different locations within the reactor toincreases the Oxidizing Agent concentration.

FIG. 10 shows a reactor 420 that may be useful for very viscous mixtures(e.g., for feed ratios of 5:1 to 1:2 of polyethylene to Oxidizing Agenton a mass basis) or for polyethylene that has not been pre-treated. Herethe polyethylene is added into a hopper 422 with the Oxidizing Agent.This mixture is pulled into the entrance of a reactor tube 424 with ascrew auger (single or twin). The auger blades are designed to both mixand convey the mixture down the reactor 420. The reactor walls areheated and as the fluid mixture moves down the reactor the polyethyleneand Oxidizing Agent continue to react. The auger can act to mix andbreakdown the polyethylene. This reactor system can have multiplesections with breaks 428 that allow for separation of any Reactant Gasand reintroduction of fresh Oxidizing Agent. The fresh Oxidizing Agentcould also be added through holes in the reactor walls at specifiedlocations down the length of the reactor tube.

Various materials can be employed for construction of the reactor,impeller, piping and valves (some options include wetted parts to bemade of Teflon, hastelloy C, glass reinforced steel, titanium, tantalum,fiberglass reinforced plastic, glass, glass-lined steel). Othervariables to be considered include:

-   Size of the reactor (length and diameter) and pipe sizing.-   Temperature of reactor: 50° C. to 300° C.-   Pressure of reactor: 10 torr to 10 bar.-   Type of reactor (stirred tank, plug flow, slurry).-   Mode of operation (batch, semi-batch, continuous).-   There may be a reactor train of multiple reactors in parallel or    series. These reactors may be of the same or different size and    type.-   Heating source (induction heating, jacketed with oil, etc.).-   Reactor may be insulated or jacketed.-   Temperature of the reactor or its heating element may be adjusted;    higher temperature ranges may provide harsher conditions to break    down polyethylene.-   Pressure of the reactor system may be adjusted; higher pressure    ranges may increase the rate of reaction and also allow for higher    temperatures.-   Residence time determines how long the reactants stay in the reactor    before exiting. The residence time can range from 30 minutes to 30    hours.-   Type of the feedstock and physical form of the feed.-   Reflux capacity.-   The amount of polyethylene relative to Oxidizing Agent in the feed    into the reactor on a mass basis.

5:1 to 1:2 of Polyethylene [mass]:Oxidizing Agent [mass].

1:3 to 1:10 of Polyethylene [mass]:Oxidizing Agent [mass].

1:10 to 1:20 of Polyethylene [mass]:Oxidizing Agent [mass].

1:20 to 1:50 of Polyethylene [mass]:Oxidizing Agent [mass]

1:50 to 1:100 of Polyethylene [mass]:Oxidizing Agent [mass].

1:100 to 1:500 of Polyethylene [mass]:Oxidizing Agent [mass].

The relative amount of polyethylene to the Oxidizing Agent on a massbasis will impact the type of reactor and process. For feed ratios of1:1 to 1:20, high concentrations of Oxidizing Agent to polyethylene arepreferred to keep the reaction rate high and also depolymerize thepolyethylene all of the way to a terminal state. For these cases, thereaction mixture could be viscous requiring helical or screw like mixingand conveying parts to move the mixture through the reactor (e.g., screwreactor for chemical recycle in FIG. 10) and fresh Oxidizing Agent maybe added at different locations of the reactor to keep theconcentrations high and promote the rate of polyethylene breakdown andProduct formation. In addition, multiple reactors may be used in seriesas shown in FIG. 7.

Stirred tank reactors and plug flow reactors are commercially availableas units to control chemical reactions.

Separation of Oxidizing Agent From Product Produced From Process toChemically Recycle Polyethylene

In an embodiment during this process, polyethylene is combined with anOxidizing Agent in a reactor, the polyethylene is broken down andoxidized (sequentially or simultaneously) into Product (e.g. 1 wt % to20 wt % dicarboxylic acids) water, (e.g. 10 wt % to 90 wt % of aqueousreaction content), and Reaction Gas (e.g. 10 wt % to 60 wt % NO and 40wt % to 90 wt % NO₂). One challenge is that the Product has highmiscibility with the Oxidizing Agent at and below the reactiontemperature; this can make it difficult to separate Product from theOxidizing Agent. Additionally, the Oxidizing Agent concentrationdecreases with increased polyethylene conversion due to the formation ofwater and Reaction Gas. To make the process economical, Product isseparated from the Oxidizing Agent and the Oxidizing Agent should berecycled back to the reactor. This disclosure details solutions toseparate the Product and the Oxidizing Agent and to recycle theOxidizing Agent back to the reactor.

This separation unit is a component of a system for conversion ofpolyethylene into high value chemicals. In the system, polyethylene iscombined with an Oxidizing Agent in a reactor to produce Product in theliquid phase and Reaction Gas. Polyethylene is broken down into Productthat can be used for value-adding products (e.g. performance materials,paints and coatings, lubricants, adhesives, fragrances, skincareproducts, etc.) serving as a drop-in replacement of existing chemicalintermediates, or as new chemical intermediates. By combining thisseparation step to the polyethylene recycling process, it is possible toisolate high value chemicals and to recover the majority of theOxidizing Agent. The disclosure enables recycling of the Oxidizing Agentand also limits Oxidizing Agent waste generation.

FIG. 11 shows the basic separation unit 160 for polyethylene conversionto Product. Polyethylene conversion products and an Oxidizing Agent exitthe reactors of the system in the process and are passed through anevaporator 161 or concentrator (e.g. thin film evaporator) to remove theOxidizing Agent (e.g. 10 wt % to 80 wt % of reactor stream) from theProduct. The concentrated mixture of Product and the Oxidizing Agent isthen passed through an Oxidizing Agent stripper/harvester 162 (e.g., aNutsche filter dryer) to separate Product in solid state and remainingOxidizing Agent. The separated Product is then passed through a dryer(e.g. spray dryer) 164 to remove residual Oxidizing Agent. All OxidizingAgent streams generated from the separation process are combined andpassed through an Oxidizing Agent concentrator (e.g. a distillationcolumn) as needed, and then recycled back in the reactor section of thepolyethylene conversion system to be reused. This component of thesystem is designed to recover as much as >90% of the Product and >90% ofthe Oxidizing Agent while minimizing the need to add more OxidizingAgent to the system.

-   The evaporator/concentrator 161 can be a thin film evaporator, a    centrifugal evaporator, a blow-down evaporator, a vortex evaporator    and/or combinations thereof as a single unit of multiple units in    series or parallel.-   The Oxidizing Agent stripper/harvester 162 can be a chromatography    column, a crystallizer, a liquid-liquid extractor, a Nutsche filter    dryer, and/or combinations thereof as a single unit or multiple    units in a sequence.-   The dryer 164 can be a freezer dryer, a spray dryer, a rotary dryer,    a centrifugal dryer, a vacuum dryer and/or combinations thereof as a    single unit or multiple units in a sequence.-   The Oxidizing Agent concentrator can be a distillation column, an    absorption column and/or combinations thereof as a single unit or    multiple units in a sequence.

The separation unit 160 can have many unique and process-specificfeatures tailored to the processing of Product from polyethyleneconversion. It can operate continuously and handle the specific liquidflow and chemical composition out of the reactor. If the Oxidizing Agentafter separation from Product is not at the desired concentration thenit could be sent to an Oxidizing Agent concentrator (e.g., adistillation column) to be further purified for direct introduction intothe reactor.

Another unique application would be to combine the separation unit withan absorption column. Reaction Gas emitted in the separation unit can becombined with Reaction Gas absorption unit to regenerate the OxidizingAgent for direct introduction into the reactor.

FIG. 12 shows modifications to separation unit 160. The concentratedProduct (e.g. 15 wt % to 80 wt % dicarboxylic acids) and Oxidizing Agent(e.g., 5 wt % to 85 wt % nitric acid) can be passed through a filter 163(e.g., a Nutsche filter) to collect the Oxidizing Agent and directlyintroduce the Oxidizing Agent into the reactor for polyethyleneconversion. Additionally, in cases where reaction species fromincomplete conversion of polyethylene are exiting out of the reactor,filtration step helps to recover such species and the Oxidizing Agent inthe filtrate which can be re-introduced into the reactor for furtherconversion to Product. The filter 163 can be gravity filter, vacuumfilter, turbo filter, centrifugal filter, a membrane filter, and/orcombinations thereof.

FIG. 13 shows additional modifications. The concentrated Product (e.g.,15 wt % to 80 wt % dicarboxylic acids) and Oxidizing Agent (e.g., 45 wt% to 95 wt % nitric acid) is first centrifuged 169 and then passedthrough a filter 163. Centrifugation settles solid particles in theconcentrated Product and Oxidizing Agent mixture, minimizes clogging offilter pores and accelerates the filtration process.

Alternatively, the Oxidizing Agent can be directly collected aftercentrifugation and directly introduced into the reactor without anadditional filtration step as shown in FIG. 14. Centrifugation can alsobe applied depending on the viscosity of the concentrated Product andOxidizing Agent mixture. Highly viscous mixtures are difficult to filterand an added step of centrifugation can be highly efficient forseparation of Product from the Oxidizing Agent.

FIG. 14 shows the process in FIG. 13 without the filtration step afterthe centrifugation.

FIG. 15 shows additional modification to FIG. 11. The system eliminatesevaporator/concentrator step, as in some cases, it can be combined withthe Oxidizing Agent stripper/harvester. In cases where loss of OxidizingAgent from separation is low, extra equipment for Oxidizing Agent andProduct recovery may not be required and completely eliminated orpossibly combined in a single step.

FIG. 16 shows a separation unit 160 with a dryer 164 (e.g., a spraydryer) to directly obtain dry Product (e.g. 90 wt % to 99.9 wt %dicarboxylic acids) and Oxidizing Agent (e.g., 45 wt % to 95 wt % nitricacid) in a single step. Rapid drying of liquid stream out of the reactorcan be achieved by blowing hot air into the stream to remove most of theOxidizing Agent. This method can be applied for liquid streams with lowviscosity that can be easily dispersed into controlled size smalldroplets.

FIG. 17 shows separation unit 160 with combined filtration and drying ina single step. This can be accomplished with a filter dryer 167 (e.g., aNutsche filter) at a desired temperature and can be operated eitherunder vacuum or at pressure. The method can be used with or withoutagitation depending on required drying rate. Faster drying is possiblewith agitation and changing the speed of agitation. Vacuum filtrationcan also be applied for faster drying. Other variables include:

-   polyethylene processed liquid stream flow rate into the    evaporator/concentrator.-   Residence time of liquid stream in the evaporator. This can be    modified to alter the amount of Oxidizing Agent removal and may also    be modified depending on the flow rate of liquid stream out of the    reactor.-   The temperature of the evaporator/concentrator (e.g. thin film    evaporator) may be adjusted to adjust evaporation rate required    based on flow rate out of the reactor and into the separation unit.    Faster flow rate out of the reactor would require higher temperature    and slower flow rate out of the reactor would require lower    temperature.-   The pressure of the evaporator/concentrator. Faster evaporation can    be achieved at lower temperature with reduced pressure and at higher    temperature with higher pressure. Operating the    evaporator/concentrator at reduced or increased pressure may add    extra cost and potentially other pieces of equipment.-   The evaporator/concentrator can be a single unit for cumulative    removal of Oxidizing Agent or multiple units for sequential removal    of the Oxidizing Agent-   Oxidizing Agent stripper/harvester may be at ambient or reduced    pressure. Reduced pressure improves filtration rates but this adds    cost and potentially other pieces of equipment like vacuum pumps.-   Temperature and pressure of the dryer.-   Temperature of the condenser.-   Speed of the centrifuge.-   Temperature and pressure of the Oxidizing Agent concentrator. Faster    evaporation can be achieved at lower temperature with reduced    pressure and at higher temperature with higher pressure.-   Pore size of the filter.-   Materials of construction for evaporator/concentrator, filter,    dryer, distillation, Oxidizing Agent stripper/harvester, centrifuge    (some options include wetted parts to be made of Teflon, hastelloy    C, glass reinforced steel, titanium, tantalum, fiberglass reinforced    plastic, glass, glass-lined steel).-   Heating source for evaporator/concentrator, distillation/dryer,    Oxidizing Agent stripper/harvester (induction heating, jacketed with    oil).

Oxidizing Agent Recovery and Regeneration for Polyethylene ChemicalRecycling

In an embodiment of this process, Reaction Gas is formed after theOxidizing Agent oxidizes the polyethylene. Commercially, nitric acid isproduced from absorption of NO_(x)—generated from ammonia—into water,using absorption column in continuous mode of operation. These plantsare typically designed to produce significant volumes of nitric acid andthus, the absorption columns are tailored to this application. We arecurrently not aware of this technology being applied to polyethylenerecycling. Furthermore, many features of the chemical recycling processare unique. In addition to Oxidizing Agent recovery, the Reaction Gas isreduced to below a threshold level, as defined by state or regionalregulations, to be released into the environment. The absorption columnmay be capable of reducing the Reaction Gas composition to these levels.

This absorption/reaction unit is a component of a chemical recyclingsystem. In the system, polyethylene is combined with an Oxidizing Agentin a reactor to produce Product in the liquid phase and a Reaction Gas.The Reaction Gas can be absorbed in water and reacted and converted backinto Oxidizing Agent. By combining this absorption step to the chemicalrecycling process it is possible to recover the majority of the producedReaction Gas enabling recycle of the Oxidizing Agent and also limitingemission of Reaction Gas out of the process. The tail gases out of theprocess are scrubbed gases (e.g. <1 wt % NO and <1 wt % NO₂).

FIG. 18 shows the basic absorption unit 140 for polyethylene chemicalrecycling. The Reaction Gas (e.g. 10-60 wt % NO and 40-90 wt % NO₂)exits the reactor and other process units and are combined and thenmixed with air, enriched air, or oxygen to convert the Reaction Gas intoan oxidized state (e.g. conversion of NO to NO₂). The gases then flowinto and are distributed at the bottom of an absorption column 140. TheReaction Gas flows up the column that has internals 142 (trays or otherpacking) to enhance contacting area and transport of the Reaction Gasinto the aqueous phase to reach equilibrium at all positions within thesystem. Pure water is added at the top of the absorption column 140 andabsorbs the Reaction Gas that react and transform into the OxidizingAgent (e.g. NO, NO₂, N₂O₃, and N₂O₄ react with water to form HNO₃)continually becoming more concentrated in Oxidizing Agent as ittraverses toward the column bottom. At the bottom of the column 140, theOxidizing Agent can reach high concentrations (e.g. 40 wt % to 70 wt %HNO₃). The Oxidizing Agent is then recycled back in the reactor sectionof the chemical recycling system to be reused. This component of thesystem is designed to recover as much as 99.9% of the Reaction Gas andconvert back into Oxidizing Agent to minimize the need to add moreOxidizing Agent into the system. The high recovery rate also permits thescrubbed gas to be emitted to the atmosphere if the concentration ofReaction Gas is low enough.

For example, the Reactor Gas may exit the reactor with a composition of50 mol % NO and 50 mol % NO₂. If this flows at 1 kmol per hour then 0.5kmol of NO can be oxidized to NO₂. Air with a flow rate of greater thanor equal to 1.7 kmol per hour to be mixed with this Reaction Gas streamto provide sufficient oxygen to oxidize the NO. After the NO is oxidizedto NO₂ the mixed stream will have N₂ and mostly NO₂ (and other lowerconcentration species found in air). The stream will have ˜1 kmol perhour of NO₂ and ˜1.35 kmol per hour of N₂. The mixed stream will be sentthrough the absorption column 140 and the NO₂ will absorb into the waterin the column ultimately converting the majority of the NO₂ back intothe Oxidizing Agent (e.g. converting the HNO₃ into a flow rate of 1 kmolper hour). The flow rate of the water is chosen to maximize theconcentration of HNO₃ in the aqueous phase.

The absorption column 140 can have many unique and process specificfeatures tailored to the polyethylene recycling process. It can operatecontinuously and handle the specific Reaction Gas composition out of thereactor (e.g. 60 wt % to 99 wt % NO₂ and 10 wt % to 60 wt % NO). Inaddition, less concentrated Oxidizing Agent from other parts of theprocess may be added to the column at intermediate stages. If theconcentration of the Oxidizing Agent exiting the absorption column 140is not high enough for the process (i.e., the concentration needed forthe reactor) then it could be sent to an additional separation unit(like a distillation column) to be further purified.

FIG. 19 shows another unique application, which combines the absorptioncolumn 140 with the reactor 120. In this system, the absorption column140 would serve multiple functions. Since the fluid in the reactor 120is at the boiling point and both Reaction Gas and Oxidizing Agent exitthe reactor 120 in the gas phase, a reflux component is necessary tore-condense the vaporized Oxidizing Agent. By adding an absorptioncolumn 140 with cold water on the top, it is possible for the absorptioncolumn 140 to perform two functions: absorption of the Reaction Gas anddirect condensation of the vaporized Oxidizing Agent.

FIG. 20 shows another modification would be to perform partialabsorption in the reflux section of the reactor. Here a packed column140 is located on the top of the reactor 120. Near the bottom of thecolumn 140 there is a tray or some internal to partially removecondensed liquid for the column. This liquid is pumped through a cooler148 to further reduce the temperature (e.g., 90° C. to 150° C.) and thenis sprayed from the top of the column 140 onto packing material withinthe column 140. The Reaction Gas exiting the reactor 120 is cooled andthe vaporized Oxidizing Agent re-condenses and drains back into thereactor 120. Because Oxidizing Agent is being consumed, theconcentration in the reactor 120 and vapor is less than theconcentration of the Oxidizing Agent in the feed, so some Reaction Gaswill be absorbed. This will reduce the amount of Reaction Gas going tothe next section and also help to keep the Oxidizing Agent concentrationhigh.

Other variables include:

-   The temperature of the water and Reaction Gas may be adjusted prior    to entering the absorption column or cooled within the column (e.g.    5° C. to 50° C.). Typically, the colder the fluids the better the    recovery and conversion to Oxidizing Agent.-   Pressure may also be adjusted. High pressure improves recovery and    separations, but this adds cost and potentially other pieces of    equipment, like compressors.-   Relative flow rates of the Reaction Gas to the water. These flow    rates will impact the composition of the scrubbed gas and the    aqueous Oxidizing Agent.-   The length of the column and the diameter.-   The internals and packing of the column.-   Number of columns.-   Location in the column where streams are added.

Definitions and Embodiments

Oxidizing Agent: chemical component(s) used to enable the reaction

The Oxidizing Agent comprises at least one selected from the groupconsisting of nitric acid, sulfuric acid, hydrogen peroxide, molecularoxygen, ozone, and combinations thereof.

In some embodiments, the Oxidizing Agent comprises at least one selectedfrom the group consisting of aqueous nitric acid, aqueous sulfuric acid,aqueous hydrogen peroxide, molecular oxygen, ozone, and combinationsthereof.

In some embodiments, the Oxidizing Agent comprises aqueous nitric acid.

In some embodiments, the Oxidizing Agent comprises 45-95 wt % aqueousnitric acid.

In some embodiments, the Oxidizing Agent comprises 50-75 wt % aqueousnitric acid.

In some embodiments, the Oxidizing Agent comprises 60-70 wt % aqueousnitric acid.

In some embodiments, the Oxidizing Agent comprises 70-80 wt % aqueousnitric acid.

Catalyst: chemical component(s) used to enhance the reaction.

The Catalyst comprises at least one selected from the group consistingof hydrochloric acid, hydrobromic acid, zinc oxide, titanium oxide,zirconium oxide, niobium oxide, zeolite, alumina,silico-alumino-phosphate, iron carbonate, calcium carbide, sulfatedzirconia, and combinations thereof.

In some embodiments, the Catalyst comprises zeolite.

In some embodiments, the Catalyst comprises ZSM-5 zeolite.

In some embodiments, the Catalyst comprises alumina.

In some embodiments, the Catalyst comprises hydrochloric acid.

Polyethylene: feedstock(s) for the reaction.

Polyethylene comprises at least one selected from the group consistingof very low density polyethylene, low density polyethylene, linear lowdensity polyethylene, medium density polyethylene, cross-linkedpolyethylene, high density polyethylene, high density cross-linkedpolyethylene, high molecular weight polyethylene, ultra-low molecularweight polyethylene, ultra-high molecular weight polyethylene, andcombinations thereof.

In some embodiments, Polyethylene comprises at least one selected fromthe group consisting of low density polyethylene, linear low densitypolyethylene, high density polyethylene, and combinations thereof.

In some embodiments, Polyethylene is from a waste source.

In some embodiments, Polyethylene has at least one contaminant selectedfrom the group consisting of pigments, additives, dirt, grease, debris,glass, paper, fluids, and combinations thereof.

In some embodiments, Polyethylene may be in the form of at least oneselected from the group consisting of films, flakes, shreds, powders,rigids, resins, melts, and combinations thereof.

Reaction Gas: gas(es) produced during the reaction

Reaction Gas comprises at least one selected from the group consistingof N₂, O₂, Ar, CO₂, H₂O, CO, NO, NO₂, N₂O, N₂O₃, N₂O₄, N₂O₅, HNO₃, SO₂,SO₃, Cl₂, Br₂, VOCs, and combinations thereof.

In some embodiments, Reaction Gas comprises NO₂, NO, HNO₃, CO, CO₂, andH₂O.

In some embodiments, Reaction Gas comprises 10 to 60 wt % NO and 40 to90 wt % NO₂.

In some embodiments, Reaction Gas comprises 10 to 60 wt % NO and 60 to99 wt % NO₂.

In some embodiments, Reaction Gas comprises 10 to 40 wt % NO, 40 to 99wt % NO₂, 0 to 10 wt % CO, 0 to 5 wt % CO₂, 0 to 10 wt % HNO₃, and 0 to10 wt % H₂O. In some embodiments, Reaction Gas comprises 10 to 40 wt %NO, 40 to 99 wt % NO₂, 0 to 10 wt % CO, 0 to 5 wt % CO₂, 0 to 10 wt %HNO₃, 0 to 10 wt % H₂O, and 0 to 10 wt % VOCs.

Product: Harvestable Chemical Output(s) From the Reaction

Product comprises at least one selected from the group consisting of C2dicarboxylic acid, C3 dicarboxylic acid, C4 dicarboxylic acid, C5dicarboxylic acid, C6 dicarboxylic acid, C7 dicarboxylic acid, C8dicarboxylic acid, C9 dicarboxylic acid, C10 dicarboxylic acid, C11dicarboxylic acid, C12 dicarboxylic acid, C13 dicarboxylic acid, C14dicarboxylic acid, C15 dicarboxylic acid, C16 dicarboxylic acid, C17dicarboxylic acid, C18 dicarboxylic acid, C19 dicarboxylic acid, C20dicarboxylic acid, C20+ dicarboxylic acid, C2 monocarboxylic acid, C3monocarboxylic acid, C4 monocarboxylic acid, C5 monocarboxylic acid, C6monocarboxylic acid, C7 monocarboxylic acid, C8 monocarboxylic acid, C9monocarboxylic acid, C10 monocarboxylic acid, C11 monocarboxylic acid,C12 monocarboxylic acid, C13 monocarboxylic acid, C14 monocarboxylicacid, C15 monocarboxylic acid, C16 monocarboxylic acid, C17monocarboxylic acid, C18 monocarboxylic acid, C19 monocarboxylic acid,C20 monocarboxylic acid, C20+ monocarboxylic acid, and combinationsthereof.

In some embodiments, Product comprises at least one selected from thegroup consisting of succinic acid, glutaric acid, adipic acid, pimelicacid, azelaic acid, or the salts or esters thereof, and at least one ofoxalic acid, suberic acid, sebacic acid, undecanedioic acid,dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid,pentadecanedioic acid, 2-octenedioic acid, 2-nonenedioic acid,2-decenedioic acid, and 2-undecenedioic acid, and salts, esters, andcombinations thereof.

In some embodiments, Product comprises at least one selected from thegroup consisting of 5-50% succinic acid, 5-50% glutaric acid, 5-50%adipic acid, 5-50% pimelic acid, 0-30% suberic acid, 0-30% azelaic acid,0-20% sebacic acid, 0-10% undecanedioic acid, 0-10% dodecanedioic acid,and combinations thereof.

In some embodiments, Product comprises at least one selected from thegroup consisting of succinic acid, glutaric acid, adipic acid, pimelicacid, and azelaic acid, sebacic acid, and combinations thereof.

In some embodiments, Product further includes at least one of C₈-C₂₀dicarboxylic acid substituted with a single nitro group, or the salts oresters thereof. In some embodiments, the C₈-C₂₀ dicarboxylic acidsubstituted with a single nitro group may be nitro-suberic acid,nitro-azelaic acid, nitro-sebacic acid, nitro-undecanedioic acid,nitro-dodecanedioic acid, nitro-brassylic acid, nitro-tetradecanedioicacid, nitro-pentadecanedioic acid, nitro-hexadecanedioic acid,nitro-heptadecanedioic acid, nitro-octadecanedioic acid,nitro-nonadecanedioic acid, and nitro-icosanedioic acid, or the salts oresters thereof. In some embodiments, the C₈-C₂₀ dicarboxylic acid is2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid,2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, or 2-nitro-icosanedioic acid, or the saltsor esters thereof.

In some embodiments, Product comprises nitrated carboxylic acids.Product may include at least one of 2-nitro-suberic acid,2-nitro-azelaic acid, 2-nitro-sebacic acid, 2-nitro-undecanedioic acid,2-nitro-dodecanedioic acid, 2-nitro-brassylic acid,2-nitro-tetradecanedioic acid, 2-nitro-pentadecanedioic acid,2-nitro-hexadecanedioic acid, 2-nitro-heptadecanedioic acid,2-nitro-octadecanedioic acid, 2-nitro-nonadecanedioic acid, and2-nitro-icosanedioic acid, or the salts or esters thereof.

In some embodiments, at least one species in the Product may be achemical intermediate for industrial applications.

It should be understood that this invention is not limited to theparticular methodologies, protocols, and reagents, etc., describedherein and as such can vary therefrom. The terminology used herein isfor the purpose of describing particular embodiments only, and is notintended to limit the scope of the present invention, which is definedsolely by the claims.

EXAMPLES

The invention is further illustrated by the following examples which areintended to be purely exemplary of the invention, and which should notbe construed as limiting the invention in any way. The followingexamples are illustrative only, and are not intended to limit, in anymanner, any of the aspects described herein. The following examples areprovided to better illustrate the claimed invention and are not to beinterpreted as limiting the scope of the invention. To the extent thatspecific materials are mentioned, it is merely for purposes ofillustration and is not intended to limit the invention. One skilled inthe art may develop equivalent means or reactants without the exerciseof inventive capacity and without departing from the scope of theinvention.

Example 1

The feedstock for Example 1 was contaminated plastic film from amaterial recovery facility. The composition of these films includesLDPE, HDPE, as well as a miscellaneous category that was not identified.The contaminated plastic film was cut into 2-inch sized squares andstrips.

5 grams of feedstock was placed into a glass lined reactor. 75 mL of 20%nitric acid, diluted with water, was added to the reactor and theplastics were submerged in the liquid solution. The reactor was sealed,pressurized with air (600 psi), and heated while the contents werestirred at 500 rpm. Once the desired temperature (120° C.) was reached,the reaction was timed for 2 hours. Then, the reactor was allowed tocool to room temperature while stirring continued.

After the pressure was released, 30 mL of acetone was added to thereactor and stirred for another 10 minutes to help the remaining solidpieces detach from the stirrer. The contents of the reactor werefiltered through filter paper, removing the solids, which is anoligomeric resin. 50 mL of 5M NaOH was added to the liquid, achieving pH12-13. A precipitate is formed and collected via filter paper; this isthe NaOH product. To the remaining liquid, 4 mL of 10M HCl was added,achieving pH 2. A precipitate is formed. The solution was placed at 4Cfor 30 minutes to allow more precipitation. This precipitate was alsocollected via filter paper; this is the HCl product. The remainingfiltrate was evaporated completely by boiling on a hot plate. 20 mLacetone was added to the dried crystals. The medium was mixed byvortexing. The non-dissolved crystals were removed via filter paper. Theremaining clear filtrate was placed at 50° C. overnight to allow slowevaporation. Finally, the dried solids were collected; this is theacetone product.

TABLE 1 Data According to Example 1. NaOH HCl Acetone Oligomers productproduct product Succinic Glutaric Adipic Pimelic Crude acids (% yield by(% yield by (% yield by (% yield by acid acid acid acid (% yield byweight) weight) weight) weight) (ppm) (ppm) (ppm) (ppm) weight) 28 43 1616 14 19 13 19 48

Examples 2a-2d

The feedstock for Examples 2a-2d was contaminated plastic film from amaterial recovery facility. The composition of these films includesLDPE, HDPE, as well as a miscellaneous category that was not identified.The contaminated plastic film was cut into 2-inch sized squares andstrips.

X grams of feedstock was placed into a glass lined reactor. Y mL of 20%or 25% nitric acid was added to the reactor and the plastics weresubmerged in the liquid solution. The reactor was sealed, pressurizedwith air (600 psi), and heated. Once the desired temperature (120° C.)was reached, the reaction was timed for 2 hours. After the first hour,stirring (500 rpm) was implemented and continued for the rest of thereaction. Then, the reactor was allowed to cool to room temperaturewhile stirring continued. (See Table 2 below for specific numeric valuesfor X and Y used in Examples 2a-2d.).

After the pressure was released, the solid phase was separated from theliquid phase by filtration. The solid phase was air dried while theliquid phase was heated on a hot plate. The solid phase contains theoligomers. To avoid burning or charring the remains of the liquid phase,the solution was removed from the heat source and allowed to air dryuntil all liquid is gone. This remaining product contains the crudedicarboxylic acids.

TABLE 2 Data According to Examples 2a-2d. Nitric acid Oligomers Crudeacids Example Feedstock (volume, (% yield by (% yield by No. mass (g)concentration) weight) weight) 2a 5  75 mL, 20% 87 24 2b 9 135 mL, 25%66 41 2c 8 120 mL, 25% 83 27 2d 12 180 mL, 25% 70 50

Example 3

The feedstock for Example 3 was LDPE bubble packaging film. The LDPEbubble packaging film was cut into 2-inch sized squares and strips.

5 grams of feedstock was placed into a glass lined reactor. 75 mL of 20%nitric acid, diluted with water, was added to the reactor and theplastics were submerged in the liquid solution. The reactor was sealed,pressurized with air (600 psi), and heated; the stirrer was not used.Once the desired temperature (120° C.) was reached, the reaction wastimed for 2 hours. Then, the reactor was allowed to cool to roomtemperature.

This example (i.e., Example 3) followed the same product collectionmethod as described in Example 2.

TABLE 3 Data According to Example 3. Oligomers (% yield by weight) Crudeacids (% yield by weight) 67 26

Example 4

The feedstock for Example 4 was HDPE pellets, each with a 0.5 cmdiameter. The reaction and product collection procedures are asdescribed in Example 3.

TABLE 4 Data According to Example 4. Oligomers (% yield by weight) Crudeacids (% yield by weight) 88 32

Examples 5a-5c

The feedstock for Examples 5a-5c was contaminated plastic film from amaterial recovery facility. The composition of these films includesLDPE, HDPE, as well as a miscellaneous category that was not identified.The surface contamination included dirt, debris, food residue, andgreases. These films were shredded into non-uniform pieces with averagesize 20 cm×20 cm.

X grams of feedstock was placed into a round bottom flask. Y mL of 69%nitric acid was added to the flask; the plastics were submerged in theliquid solution. The bottom of the flask was heated in a heating mantle;the opening of the flask was connected to a condenser. A stir bar wasused to agitate the contents. Once the desired temperature (120° C.) wasreached, the reaction was timed for Z hours. Then, the flask was allowedto cool to room temperature while stirring continued. (See Table 5 belowfor specific numeric values for X, Y and Z used in Examples 5a-5c.).

Subsequently, filtration via filter paper was performed to separate theoligomeric resin from the liquid solution. The liquid solution washeated to 130° C. for 60 minutes to remove the nitric acid. Theremaining crystalline solid comprised the dicarboxylic acid products.

TABLE 5 Data According to Examples 5a-5c. Nitric acid Reaction OligomersCrude acids Example Feedstock volume time (% yield by (% yield by No.mass (g) (mL) (hours) weight) weight) 5a 15 60 6 76 31 5b 30 105 12 7934 5c 30 150 24 51 70

Examples 6a-6d

The feedstock for Examples 6a-6d was contaminated plastic film from amaterial recovery facility. The composition of these films includesLDPE, HDPE, as well as a miscellaneous category that was not identified.The surface contamination included dirt, debris, food residue, andgreases. These films were shredded into non-uniform pieces with averagesize 20 cm×20 cm.

X grams of feedstock was placed into a round bottom flask. Y mL of 69%nitric acid and Z grams of solid state catalyst were added to the flask;the plastics were submerged in the liquid solution. The bottom of theflask was heated in a heating mantle; the opening of the flask wasconnected to a condenser. A stir bar was used to agitate the content.Once the desired temperature was reached, the reaction was timed for Khours. Then, the flask was allowed to cool to room temperature whilestirring continued. (See Table 6 below for specific numeric values forX, Y, Z and K used in Examples 6a-6d.).

Subsequently, filtration via filter paper was performed to separate thesolids (oligomeric resin and solid state catalyst) from the liquids.Distillation was performed on the liquid solution for a period of 1 hourto recover the nitric acid. The remaining crystalline solids were placedin the desiccator overnight. The weight of the dried crystals was 40percent of the initial weight of the films. This solid comprised amixture of C4-C10 dibasic acids.

TABLE 6 Data According to Examples 6a-6d. Feedstock Nitric acid SolidState Reaction Oligomers Crude acids Example mass content Catalyst time(% yield by (% yield by No. (g) (mL) (g) (hours) weight) weight) 6a 30105 3 3 138 58 (zeolite) 6b 30 150 1 24 36 80 (zeolite) 6c 40 150 3 2475 36 (zeolite) 6d 30 150 1 5 87 55 (alumina)

Example 7

200 mg of LDPE (cut from air/bubble packaging) was added to a 100 mLglass lined stainless steel pressure reactor, which was sealed. Thereactor was purged with N₂, and then pressured to 40 psi with NO, 460psi with N₂, and 100 psi with O₂. The reactor was heated to 110° C. for1 hour, following which it was cooled and the pressure released. Theresulting crude product mixture (decomposition mixture) was removed andextracted with methanol. The methanol soluble product mixture recoverywas 69% by weight and consisted of dibasic acids.

Example 8

200 mg of LDPE (cut from air/bubble packaging) and 200 mg HDPE (cut froma plastic grocery bag) were added to a 100 mL glass lined stainlesssteel pressure reactor, which was sealed. The reactor was purged withN₂, and then pressured to 40 psi with NO, 460 psi with N₂, and 100 psiwith O₂. The reactor was heated to 120° C. for 2 hours, following whichit was cooled and the pressure released. The resulting crude productmixture (decomposition mixture) was removed and extracted with methanol.The methanol soluble product mixture recovery was 49% by weight. Aftermethanol removal, the remaining crude product comprised dicarboxylicacids detected as their respective dimethyl esters.

Analysis

Qualitative and quantitative analysis of the acid products wereperformed by GC-MS on a DB-1 column. The crude products mentioned in theabove examples esterified overnight with methanol in the presence ofacetyl chloride. The derivatized products were filtered and then diluted25×-100× in methanol.

Calibration curves were constructed for four major compounds: dimethylsuccinate (C4), dimethyl glutarate (C5), dimethyl adipate (C6), anddimethyl pimelate (C7). Quantitation was based on the TIC and thepercentage values were calculated based on the mass of each sample. TheGC-MS has also identified longer chain dimethyl esters, such as dimethylsuberate (C8), dimethyl azelate (C9), dimethyl sebacate (C10), andoccasionally undecanedioic acid dimethyl ester (C11), and dodecanedioicacid dimethyl ester (C12), but these were not quantified. Such achromatogram can be seen in FIG. 2.

Oligomeric resins were preliminarily characterized by thermogravimetricanalysis (TGA) and differential scanning calorimetry (DSC). Theseoligomeric resins possessed different chemical properties from theoriginal PE feedstock. FIG. 3A-FIG. 3B contrasts the decompositionpatterns between oligomeric resin (FIG. 3A) and PE (FIG. 3B).

FIG. 4 shows that while the waste PE film has crystallinity around 120°C., while the resin product has lost crystallinity.

Example 9

The feedstock for this example was 10 g polyethylene and 100 g 70 wt %aqueous nitric acid. The batch reaction was conducted for 9 hours at120° C. and atmospheric pressure. The products were dicarboxylic acids(50-65 wt %) and a separate fraction (35-50 wt %) containing othercomponents including nitro-substituted dicarboxylic acids. Thedicarboxylic acids were separated by distillation of the reactionfiltrate followed by evaporation to remove the majority of aqueousnitric acid. Table 7 provides the ranges of various dicarboxylic acidsthat were found in that fraction.

TABLE 7 Dicarboxylic acid Wt % Oxalic acid (C2) 0-10% Malonic acid (C3)   0% Succinic acid (C4) 5-18% Glutaric acid (C5) 8-28% Adipic acid (C6)10-29%  Pimelic acid (C7) 10-20%  Suberic acid (C8) 9-20% Azelaic acid(C9) 8-13% Sebacic acid (C10) 1-10% Undecanedioic acid (C11)  1-8%Dodecanedioic acid (C12)  0-5% Tridecanedioic acid (C13)  0-4%Tetradecanedioic acid (C14)  0-2% Pentadecanedioic acid (C15) 0-0.4% 

Example 10

A 250 mL round bottom flask equipped with a magnetic stir bar was loadedwith 10 g polyethylene and 100 g 67 wt % HNO₃. The reaction flask wasequipped with a glass thermometer, placed onto a temperature controlledIKA heating plate and attached to a water condenser. The reaction flaskwas stirred at maximum stir rate (2000 RPM setting) and heated to adesired reaction temperature. The beginning of the reaction time wasmarked once the desired temperature has been reached (˜15-20 mins).After reaction time, the heater was turned off, the reaction flasklifted from the heater, and quickly cooled while stirring (˜15-20 mins).The final mixture (aqueous product stream) was filtered through a filterpaper on a Hirsch funnel into a 250 mL beaker. Filtrate collected in the250 mL beaker was evaporated on a hot plate at 75° C. to obtain crudedicarboxylic acid product. The crude dicarboxylic acid was subjected toGC analysis for dicarboxylic acid composition and LC analysis foradditional product composition. The results are shown in Table 8.

TABLE 8 Dicarboxylic acid Wt % Oxalic acid (C2)     0% Malonic acid (C3)    0% Succinic acid (C4) 10-11% Glutaric acid (C5) 15-18% Adipic acid(C6) 16-18% Pimelic acid (C7) 15-17% Suberic acid (C8) 13-15% Azelaicacid (C9) 10-12% Sebacic acid (C10)  5-9% Undecanedioic acid (C11)  3-6%Dodecanedioic acid (C12)  1-3% Tridecanedioic acid (C13) 0.5-1.5% Tetradecanedioic acid (C14)  0-0.2% Pentadecanedioic acid (C15)  0-0.2%

Example 11

Powdered pure polyethylene was added to a beaker and 67 wt % aqueousnitric acid was added at a mass ratio of 10:1 aqueous nitric topolyethylene. The mixture was heated at 120° C. for 6 hours and a sampletaken for analysis by quadrupole time of flight liquid chromatographymass spectrometry (QTOF-LCMS). The major compounds detected wheredicarboxylic acids and their nitration products. FIGS. 22A-C provide asummary of the LCMS results for the sample.

Example 12

The make the methyl esters of dicarboxylic acids for analysis, in a 20mL scintillation vial, ˜60 mg of sample was dissolved in ˜6 g of MeOH.˜200 uL of AcC1 was added. (Addition of AcC1 is exothermic and henceaddition is performed dropwise in small scale and in ice bath in largescale.) The target concentration for above solution was aimed to be˜10000 ppm. If >10000 ppm, required dilution was performed. ˜1 mL ofsolution, with 10000 ppm sample, was transferred to an 8 mL vial. And175 mg of anhydrous Na₂SO₄ was added. The mixture was placed in a 40° C.oven or a hot plate for 1 hour. After 1 hour, the mixture was cooled toRT and 40× dilution was performed. For each dilution and solutionpreparation, masses and densities were recorded so that their respectivevolumes could be calculated. The results are shown in FIG. 23.

Example 13

This Example shows the effect of pressure and temperature on thereaction products.

2 Grams of polyethylene (PE) powder and 20 grams of 25% nitric acid(1:10 PE to nitric acid ratio) were added to a 100 mL glass liner. Theliner was loaded into a 100 mL Parr reactor vessel made of corrosionresistant carpenter 20 material and clamped to the reactor head. TheParr reactor was equipped with gas lines for adding gases, pressuregauge, digital pressure sensor, magnetic stirrer, thermocouple and aceramic heater. A controller was used to control the heating andstirring in the reactor.

Nitrogen gas was purged three times to remove any oxygen/air inside thevessel. Then the vessel was pressurized and leak test was performed todetect any leaks, indicated by pressure drop over time. Leaks were fixedand leak test was repeated until no leaks were detected, and then thereactor was depressurized.

The heater (set to 120° C. to 180° C.) and stirrer (set to 300 RPM) wereturned on via the controller. As the temperature inside the reactionvessel reached the desired temperature (˜15-20 min), the start time wasrecorded the reaction proceeded for 6 hours. (Since this was a closedsystem, as the temperature increased, the pressure inside the reactionvessel also increase due to the increased liquid volume and thegeneration of gases.)

After the reaction was complete, the reaction vessel was cooled by anexternal fan to room temperature (˜20-30 min). Then, gases were ventedand nitrogen was purged to remove any leftover gases before the reactorwas opened.

The Product mixture, which contained a solid stream (unreacted orincompletely reacted PE) and a liquid stream (dicarboxylic aciddissolved in nitric acid), was separated via gravity filtration. Thedilute nitric acid in the liquid stream was removed via distillation andthe remaining solids (which contained dicarboxylic acid) was analyzedusing GC-MS. The results are shown in FIG. 24 and Table 9 below

TABLE 9 Temp (° C.) dicarboxylic acid yield % 120 28% 130 38% 140 39%150 42% 160 39% 180 25%

As shown in FIG. 24 and Table 9, dicarboxylic acid yield % (grams ofdicarboxylic acid produced per gram of PE feed) increased with theincrease in temperature from 120° C. to 150° C. This is believed to bebecause the higher temperatures assisted the breakdown of PE intodicarboxylic acid products. Further increase in the temperature from160° C. to 180° C. decreased the dicarboxylic acid yield % as thesehigher temperatures may have further converted dicarboxylic acid intogases and other unwanted species.

At lower nitric acid concentration, pressure reactions were able toyield more dicarboxylic acid than reactions conducted at atmosphericpressure with higher nitric acid concentration. As a comparison, areflux experiment at atmospheric pressure (70% nitric acid, 1:10 PE tonitric acid ratio, 6 hrs, 120° C., 0 Psi) resulted in a 29% dicarboxylicacid yield whereas a pressure reaction (25% nitric acid, 1:10 PE tonitric ratio, 6 hrs, 150° C., 500 Psi) resulted in a 42% dicarboxylicacid yield, with notably higher concentrations of shorter chaindicarboxylic acids (see data in Table 10 below).

TABLE 10 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 Reflux experiment 13%17% 19% 18% 15% 11% 4% 2% 0.7% 0.3% 0.04% 0.00% 150° C. pressure test40% 27% 19% 10%  4%  1% 0% 0%   0%   0%   0%   0%

The various methods and techniques described above provide a number ofways to carry out the application. Of course, it is to be understoodthat not necessarily all objectives or advantages described can beachieved in accordance with any particular embodiment described herein.Thus, for example, those skilled in the art will recognize that themethods can be performed in a manner that achieves or optimizes oneadvantage or group of advantages as taught herein without necessarilyachieving other objectives or advantages as taught or suggested herein.A variety of alternatives are mentioned herein. It is to be understoodthat some embodiments specifically include one, another, or severalfeatures, while others specifically exclude one, another, or severalfeatures, while still others mitigate a particular feature by inclusionof one, another, or several advantageous features.

Furthermore, the skilled artisan will recognize the applicability ofvarious features from different embodiments. Similarly, the variouselements, features and steps discussed above, as well as other knownequivalents for each such element, feature or step, can be employed invarious combinations by one of ordinary skill in this art to performmethods in accordance with the principles described herein. Among thevarious elements, features, and steps some will be specifically includedand others specifically excluded in diverse embodiments.

Although the application has been disclosed in the context of certainembodiments and examples, it will be understood by those skilled in theart that the embodiments of the application extend beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses and modifications and equivalents thereof.

Various embodiments of this application are described herein, includingthe best mode known to the inventors for carrying out the application.Variations on those embodiments will become apparent to those ofordinary skill in the art upon reading the foregoing description. It iscontemplated that skilled artisans can employ such variations asappropriate, and the application can be practiced otherwise thanspecifically described herein. Accordingly, many embodiments of thisapplication include all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the application unlessotherwise indicated herein or otherwise clearly contradicted by context.

All patents, patent applications, publications of patent applications,and other material, such as articles, books, specifications,publications, documents, things, and/or the like, referenced herein arehereby incorporated herein by this reference in their entirety for allpurposes, excepting any prosecution file history associated with same,any of same that is inconsistent with or in conflict with the presentdocument, or any of same that may have a limiting affect as to thebroadest scope of the claims now or later associated with the presentdocument. By way of example, should there be any inconsistency orconflict between the description, definition, and/or the use of a termassociated with any of the incorporated material and that associatedwith the present document, the description, definition, and/or the useof the term in the present document shall prevail.

It is to be understood that the embodiments of the application disclosedherein are illustrative of the principles of the embodiments of theapplication. Other modifications that can be employed can be within thescope of the application. Thus, by way of example, but not oflimitation, alternative configurations of the embodiments of theapplication can be utilized in accordance with the teachings herein.Accordingly, embodiments of the present application are not limited tothat precisely as shown and described.

Various embodiments of the invention are described above in the DetailedDescription. While these descriptions directly describe the aboveembodiments, it is understood that those skilled in the art may conceivemodifications and/or variations to the specific embodiments shown anddescribed herein. Any such modifications or variations that fall withinthe purview of this description are intended to be included therein aswell. Unless specifically noted, it is the intention of the inventorsthat the words and phrases in the specification and claims be given theordinary and accustomed meanings to those of ordinary skill in theapplicable art(s).

The foregoing description of various embodiments of the invention knownto the applicant at this time of filing the application has beenpresented and is intended for the purposes of illustration anddescription. The present description is not intended to be exhaustivenor limit the invention to the precise form disclosed and manymodifications and variations are possible in the light of the aboveteachings. The embodiments described serve to explain the principles ofthe invention and its practical application and to enable others skilledin the art to utilize the invention in various embodiments and withvarious modifications as are suited to the particular use contemplated.Therefore, it is intended that the invention not be limited to theparticular embodiments disclosed for carrying out the invention.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art that,based upon the teachings herein, changes and modifications may be madewithout departing from this invention and its broader aspects and,therefore, the appended claims are to encompass within their scope allsuch changes and modifications as are within the true spirit and scopeof this invention.

What is claimed is:
 1. A composition, comprising: a. succinic acid,glutaric acid, adipic acid, pimelic acid, and azelaic acid, or the saltsor esters thereof; and b. at least one of oxalic acid, suberic acid,sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioicacid, tetradecanedioic acid, pentadecanedioic acid, 2-octenedioic acid,2-nonenedioic acid, 2-decenedioic acid, and 2-undecenedioic acid, or thesalts or esters thereof.
 2. The composition of claim 1, wherein a.succinic acid is present in an amount of from about 5 to about 18 wt %,glutaric acid is present in an amount of from about 8 to about 28 wt %,adipic acid is present in an amount of about 10 to about 29 wt %,pimelic acid is present in an amount of about 10 to about 20 wt %, andazelaic acid is present in an amount of about 8 to about 13 wt %, or anequivalent amount of the salts or esters thereof, and b. if present,oxalic acid is present in an amount up to 10 wt %, if present subericacid is present in an amount of about 9 to about 20 wt %, if presentsebacic acid is present in an amount of about 1 to about 10 wt %, ifpresent undecanedioic acid is present in an amount of about 1 to about 8wt %, if present dodecanedioic acid is present up to about 5 wt %, ifpresent tridecanedioic acid is present up to about 4 wt %, if presenttetradecanedioic acid is present up to about 2 wt %, and if presentpentadecanedioic acid is present up to about 0.4 wt %, or an equivalentamount of the salts or esters thereof.
 3. The composition of claim 1,wherein a. succinic acid is present in an amount of from about 10 toabout 11 wt %, glutaric acid is present in an amount of from about 15 toabout 18 wt %, adipic acid is present in an amount of about 16 to about18 wt %, pimelic acid is present in an amount of about 15 to about 17 wt%, and azelaic acid is present in an amount of about 10 to about 12 wt%, or an equivalent amount of the salts or esters thereof, and b. ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of about 13 to about 15 wt %, ifpresent sebacic acid is present in an amount of about 5 to about 9 wt %,if present undecanedioic acid is present in an amount of about 3 toabout 6 wt %, if present dodecanedioic acid is present in an amount ofabout 1 to about 3 wt %, if present tridecanedioic acid is present in anamount of about 0.5 to about 1.5 wt %, if present tetradecanedioic acidis present up to about 0.2 wt %, and if present pentadecanedioic acid ispresent up to about 0.2 wt %, or an equivalent amount of the salts oresters thereof.
 4. The composition of claim 1, wherein a. succinic acidis present in an amount of from about 5 to about 40 wt %, glutaric acidis present in an amount of from about 8 to about 27 wt %, adipic acid ispresent in an amount of about 10 to about 29 wt %, pimelic acid ispresent in an amount of about 10 to about 20 wt %, and azelaic acid ispresent in an amount of about 1 to about 13 wt %, or an equivalentamount of the salts or esters thereof, and b. if present, oxalic acid ispresent in an amount up to 10 wt %, if present suberic acid is presentin an amount of to about 4 to about 20 wt %, if present sebacic acid ispresent up to about 10 wt %, if present undecanedioic acid is present upto about 8 wt %, if present dodecanedioic acid is present up to about 5wt %, if present tridecanedioic acid is present up to about 4 wt %, ifpresent tetradecanedioic acid is present up to about 2 wt %, and ifpresent pentadecanedioic acid is present up to about 0.4 wt %, or anequivalent amount of the salts or esters thereof.
 5. The composition ofclaim 1, wherein the composition further comprises: c. at least one of2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, and 2-nitro-icosanedioic acid, or thesalts or esters thereof.
 6. A composition, comprising: a. succinic acid,glutaric acid, adipic acid, pimelic acid, and azelaic acid, or the saltsor esters thereof; and b. at least one C₈-C₂₀ dicarboxylic acidsubstituted with a single nitro group, or the salts or esters thereof.7. The composition of claim 6, wherein the at least one C₈-C₂₀dicarboxylic acid substituted with a single nitro group is (1)nitro-suberic acid, nitro-azelaic acid, nitro-sebacic acid,nitro-undecanedioic acid, nitro-dodecanedioic acid, nitro-brassylicacid, nitro-tetradecanedioic acid, nitro-pentadecanedioic acid,nitro-hexadecanedioic acid, nitro-heptadecanedioic acid,nitro-octadecanedioic acid, nitro-nonadecanedioic acid, ornitro-icosanedioic acid, or the salts or esters thereof; or (2)2-nitro-suberic acid, 2-nitro-azelaic acid, 2-nitro-sebacic acid,2-nitro-undecanedioic acid, 2-nitro-dodecanedioic acid,2-nitro-brassylic acid, 2-nitro-tetradecanedioic acid,2-nitro-pentadecanedioic acid, 2-nitro-hexadecanedioic acid,2-nitro-heptadecanedioic acid, 2-nitro-octadecanedioic acid,2-nitro-nonadecanedioic acid, or 2-nitro-icosanedioic acid, or the saltsor esters thereof.
 8. The composition of claim 6, wherein the at leastone C₈-C₂₀ dicarboxylic acid substituted with a single nitro group ispresent up to 1 wt % in the composition.
 9. The composition of claim 6,further comprising: c. at least one of oxalic acid, suberic acid,sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioicacid, tetradecanedioic acid, pentadecanedioic acid, 2-octenedioic acid,2-nonenedioic acid, 2-decenedioic acid, and 2-undecenedioic acid, or thesalts or esters thereof.
 10. The composition of claim 9, wherein a.succinic acid is present in an amount of from about 5 to about 18 wt %,glutaric acid is present in an amount of from about 8 to about 28 wt %,adipic acid is present in an amount of about 10 to about 29 wt %,pimelic acid is present in an amount of about 10 to about 20 wt %, andazelaic acid is present in an amount of about 8 to about 13 wt %, or anequivalent amount of the salts or esters thereof, and c. if present,oxalic acid is present in an amount up to 10 wt %, if present subericacid is present in an amount of to about 9 to about 20 wt %, if presentsebacic acid is present in an amount of about 1 to about 10 wt %, ifpresent undecanedioic acid is present in an amount of about 1 to about 8wt %, if present dodecanedioic acid is present up to about 5 wt %, ifpresent tridecanedioic acid is present up to about 4 wt %, if presenttetradecanedioic acid is present up to about 2 wt %, and if presentpentadecanedioic acid is present up to about 0.4 wt %, or an equivalentamount of the salts or esters thereof.
 11. The composition of claim 9,wherein a. succinic acid is present in an amount of from about 10 toabout 11 wt %, glutaric acid is present in an amount of from about 15 toabout 18 wt %, adipic acid is present in an amount of about 16 to about18 wt %, pimelic acid is present in an amount of about 15 to about 17 wt%, and azelaic acid is present in an amount of about 10 to about 12 wt%, or an equivalent amount of the salts or esters thereof, and c. ifpresent, oxalic acid is present in an amount up to 10 wt %, if presentsuberic acid is present in an amount of about 13 to about 15 wt %, ifpresent sebacic acid is present in an amount of about 5 to about 9 wt %,if present undecanedioic acid is present in an amount of about 3 toabout 6 wt %, if present dodecanedioic acid is present in an amount ofabout 1 to about 3 wt %, if present tridecanedioic acid is present in anamount of about 0.5 to about 1.5 wt %, if present tetradecanedioic acidis present up to about 0.2 wt %, and if present pentadecanedioic acid ispresent up to about 0.2 wt %, or an equivalent amount of the salts oresters thereof.
 12. The composition of claim 9, wherein a. succinic acidis present in an amount of from about 5 to about 40 wt %, glutaric acidis present in an amount of from about 8 to about 27 wt %, adipic acid ispresent in an amount of about 10 to about 29 wt %, pimelic acid ispresent in an amount of about 10 to about 20 wt %, and azelaic acid ispresent in an amount of about 1 to about 13 wt %, or an equivalentamount of the salts or esters thereof, and c. if present, oxalic acid ispresent in an amount up to 10 wt %, if present suberic acid is presentin an amount of to about 4 to about 20 wt %, if present sebacic acid ispresent up to about 10 wt %, if present undecanedioic acid is present upto about 8 wt %, if present dodecanedioic acid is present up to about 5wt %, if present tridecanedioic acid is present up to about 4 wt %, ifpresent tetradecanedioic acid is present up to about 2 wt %, and ifpresent pentadecanedioic acid is present up to about 0.4 wt %, or anequivalent amount of the salts or esters thereof.
 13. The composition ofclaim 1, wherein the acids are at least partially in the form of analkaline metal salt.
 14. The composition of claim 1, wherein the acidsare at least partially in the form of esters.
 15. The composition ofclaim 14, wherein the esters are C₁₋₄ alkyl esters.
 16. The compositionof claim 1, wherein the acids are in the form of free acids.